Schorl Family. Topaz. Pyrophyllite. Euclase. Emerald. Beryl. Schorlite. Schorl. a. Common. b. Electric or Tourmaline. Piftazite. Zoisite. Axinite or Thumerstone.

Quartz Family. Quartz. a. Amethyst. Common. Fibrous. b. Rock crystal. c. Rose-coloured or milk quartz. d. Common quartz. e. Prafte. f. Ferruginous quartz, or iron flint. Hornstone. a. Splintery. b. Conchoidal. c. Ligniform. Flinty slate. a. Common. b. Lydian stone. Flint. Calcedony. a. Common. b. Carnelian. Opal. a. Precious. b. Common. d. Ligniform. Menilite. Jasper. a. Egyptian. b. Ribband. c. Porcelain. d. Common. e. Agate. f. Opal. Heliotrope or Bloodstone. Chrysopraife. Plafma. Cats eye.

Pitchstone Family. Obfidian. Pitchstone. Pearltone. Pumice.

Zeolite Family. Prehnite. a. Fibrous. b. Foliated. Zeolite. a. Mealy. b. Fibrous.

Stilbite. Cubizite, Chabasie or Ainalcime. Crofs-stone, Staurolite. Laumonite. Dipyre. Natrolite. Azurite. Lazulite. Hydrargillite.

Feldspar Family. Andalusite. Feldspar. a. Adularia. b. Labradorite stone. c. Common feldspar. d. Compact. e. Hollow spar, chiaflolite. Scapolite. Arctizite or Wernerite. Diaflore. Spodumene. Meionite. Sommitie. Ichthyophthalmite.

IV. ARGILLACEOUS Gen. Clay Family. Native alumina. Porcelain earth. Common clay. a. Loam. b. Pipe clay. c. Potters clay. d. Variegated clay. e. Slaty clay. Claystone. Adhesive slate. Polishing slate. Tripoli. Floatstone. Alum stone.

Clay Slate Family. Aluminous schifus. a. Common. b. Shining. Bituminous schifus. Drawing slate. Whet slate. Clay slate.

Mica Family. Lepidolite. Mica. Pinite. Potstone. Chlorite. a. Earthy. b. Common. c. Foliated. d. Schifus.

Trap Family. Hornblende. a. Common. b. Basaltic.

Labradore. Schifus. Basalt. Wacken. Phonolite or Clinkstone. Lava.

Lithomarga Family. Green earth. Lithomarga. a. Friable. b. Indurated. Rock soap. Umber. Yellow earth.

V. MAGNESIAN Genus. Soap Stone Family. Native magnesia. Bole. Sea froth. Fullers earth. Steatites. Figure stone.

Talc Family. Nephrite. a. Common. b. Axe-stone. Serpentine. a. Common. b. Precious. Schillerstone. Talc. a. Earthy. b. Common. c. Indurated. Asbestos. a. Mountain cork. b. Amianthus. c. Common asbestos. d. Ligniform asbestos.

Actynolite Family. Cyanite. Actynolite. a. Asbestos. b. Common. c. Glaffy. Tremolite. a. Asbestos. b. Common. c. Glaffy. Smaragdite. Sahlitie. Schalfstone.

VI. CALCAREOUS Genus. Family of Carbonates. Agaric mineral. Chalk. Limestone. a. Compact. b. Common. c. Foliated. d. Schifus.

I. Genus SULPHATES. Native vitriol. Native alum. Mountain butter. Capillary salt. Native Epsom salt. Native Glauber salt.

SECOND CLASS. SALTS.

I. Genus SULPHATES. Native vitriol. Native alum. Mountain butter. Capillary salt. Native Epsom salt. Native Glauber salt.

II. Genus Nitrates. Native nitre.

III. Genus Muriates. Rock salt. a. Foliated. b. Fibrous. Sea salt. Native sal ammoniac.

IV. Genus Carbonates. Native soda. Native magnesia.

V. Genus Borates. Boracite.

VI. Genus Fluates. Cryolite.

THIRD CLASS. COMBUSTIBLES.

I. Genus Sulphur. Native sulphur. a. Common. b. Volcanic.

II. Bituminous Genus. Petroleum, or mineral oil. Mineral pitch. a. Elastic. b. Earthy. c. Slaggy.

Amber. a. White. b. Yellow.

Brown coal. a. Common. b. Bituminous wood. c. Earth coal. d. Alum earth. e. Moor coal.

Black coal. a. Pitch coal. b. Columnar coal. c. Slaty coal. d. Cannel coal. e. Foliated coal. f. Coarse coal.

Coal blende. a. Conchoidal. b. Slaty.

III. Graphite Genus. Graphite. a. Scaly. b. Compact.

Mineral charcoal.

FOURTH CLASS. METALLIC ORES.

I. Platina Genus. Native platina.

II. Gold Genus. Native gold. a. Golden yellow. b. Brals yellow. c. Grayish yellow.

III. Mercury Genus. Native mercury. Native amalgam. Corncous ore of mercury.

Liver ore of mercury. a. Common. b. Compact. c. Foliated.

Cinnabar. a. Common. b. Fibrous.

IV. Silver Genus. Native silver. a. Common. b. Auriferous. Antimonial silver ore. Arsenical silver ore. Corneous silver ore. Sooty silver ore. Vitreous silver ore. Brittle vitreous silver ore. Red silver ore. a. Dark red. b. Bright red.

White silver ore. Black silver ore.

V. Copper Genus. Native copper. Vitreous copper ore. a. Compact. b. Foliated. Variegated copper ore. Copper pyrites. White copper ore. Gray copper ore. Black copper ore. Red copper ore. a. Compact. b. Foliated. c. Capillary. Brick red copper ore. Emerald copper ore. Azure copper ore. a. Earthy. b. Indurated.

Malachite. a. Fibrous. b. Compact.

Green copper ore. Ferruginous green copper ore. a. Earthy. b. Slaggy.

Micaceous copper ore. a. Foliated. b. Lenticular.

Muriate of copper.

VI. Iron Genus. Native iron. Iron pyrites. a. Common. b. Radiated. c. Capillary. d. Hepatic.

Magnetic pyrites. Magnetic iron ore. a. Common. b. Arenaceous.

Specular iron ore. a. Compact. b. Foliated. c. Radiated. d. Plumose.

Red iron ore. a. Red iron froth. b. Compact. c. Red haematites. d. Red ochre.

Brown iron ore. a. Brown iron froth. b. Compact. c. Brown haematites. d. Brown ochre.

Sparry iron ore. Black iron ore. a. Compact. b. Black haematites. Argillaceous iron stone. a. Red chalk. b. Columnar argillaceous iron stone. c. Granular. d. Common. e. Reniform. f. Pissiform.

Bog iron stone. a. Morally. b. Swampy. c. Meadow.

Blue earthy iron stone. Green earthy iron stone.

VII. Lead Genus. Galena. a. Common. b. Compact.

Blue lead ore. Brown lead ore. Black lead ore. White lead ore. Green lead ore. Red lead ore. Yellow lead ore. Native fulphate of lead. Earthly lead ore. a. Friable. b. Indurated.

VIII. Tin Genus. Tin pyrites. Common tinstone. Grained tin ore.

IX. Bismuth Genus. Native bismuth. Vitreous bismuth. Ochre of bismuth.

X. Zinc Genus. Blende. a. Yellow. b. Brown. c. Black.

Calamine. a. Compact. b. Foliated.

XI. Antimony. Native antimony. Gray ore of antimony. a. Compact. b. Foliated. c. Radiated. d. Plumose.

Red ore of antimony. White ore of antimony. Ochre of antimony.

XII. Cobalt Genus. White cobalt ore. Gray cobalt ore. Shining cobalt ore. Black cobalt ochre. a. Friable. b. Indurated.

Brown cobalt ochre. Yellow cobalt ochre. Red cobalt ochre. a. Earthy. b. Radiated.

XIII. Nickel Genus. Copper-coloured nickel. Nickel ochre.

XIV. Manganese Genus. Gray ore of manganese. a. Radiated. b. Foliated. c. Compact. d. Earthy.

Black ore of manganese. Red ore of manganese.

XV. Molybdena Genus. Sulphuret of molybdena.

XVI. Arsenic Genus. Native arsenic. Arsenical pyrites. a. Common. b. Argentiferous.

Orpiment. a. Yellow. b. Red.

Native oxide of arsenic.

XVII. Tungsten Genus. Wolfram. Tungstate of lime.

XVIII. Titanium Genus. Menachanite. Octahedrite. Titanite. Nigrine. Brown ore. Iferine.

XIX. Uranium Genus. Pitchy ore. Micaceous uranite. Uranite ochre.

XX. Tellurium Genus. Native tellurium. Graphic ore. Yellow ore. Black or foliated ore.

XXI. Chromium Genus. Needle ore. Ochre of chromium.

XXII. Columbium Genus.

XXIII. Tantalum Genus.

XXIV. Cerium Genus.

I. Genus. I. Genus. DIAMOND.

One Species. DIAMOND.

Id. Kirwin, I. 393. Le Diamant, Brochant, II. 153. Haüy, III. 287.

Essential character.—Scratches all other minerals.

External characters.—Its most common colours are grayish white and yellowish white; smoke gray and yellowish gray; clove brown; sometimes saffron green, passing to pistachio green and apple green; sometimes a wine yellow and citron yellow, and also blue and rose red.

When the diamond is cut, it presents a splendid and varied play of colours, which is one of its most striking characters.

It is found sometimes in rounded grains, which are supposed to have been crystals with the edges worn; but it is most frequently met with crystallized.

The primitive form is a regular octahedron, the integument molecule a regular tetrahedron; but the form which it commonly assumes is the spheroidal, with 48 curvilinear faces, six of which correspond to the same face of the primitive octahedron. Besides this form there are various others, as the double three-sided pyramid, the dodecahedron, &c. All the modifications of the crystals of the diamond, Haüy observes, seem to be the effects of its tendency to crystallize in a regular figure of 48 plane faces, which, if it ever has existed, has not yet been discovered; and it is easy to conceive that this form would be produced by intermediate decrements on all the angles of the nucleus; but the deviations from this form seem to have been occasioned by its precipitate formation.

The external lustre is from four to one; internal four. The fracture is straight foliated, with a fourfold cleavage, parallel to the faces of the octahedron; transparency four to three; hardness ten; brittle; specific gravity 3.518 to 3.600. Becomes positively electric by friction, even before it is polished.

Chemical character.—When exposed to a sufficient temperature, it is entirely consumed. This has been fully ascertained by the experiments of modern chemists, from which it is concluded, that the diamond is entirely composed of pure carbon. See Chemistry.

Mr Boyle was the first, according to Henckel, who subjected the diamond to the action of heat, and in his experiments he found that it exhaled very copious and acrid vapours. This was about the year 1673; but in the year 1694 the experiment was repeated by the order of Cosmo III., grand duke of Tuscany. Diamonds were exposed to the heat of the powerful burning glass of Tschirnhausen, the action of which was even aided by means of another burning glass; and about the end of 30 seconds a diamond of 20 grains lost its transparency, separated into small pieces, and was at last entirely dissipated. The same experiment was repeated on other diamonds, always with the same result, and without exhibiting the least sign of fusion. Newton, in his treatise on Optics, has placed the diamond among combustibles, supposing that it is a coagulated unctuous substance. He had been led to this by observing its extraordinary refractive power, which in combustible bodies he found to be in a ratio considerably higher than their density. According to this general law he concluded, that the diamond as well as water contained an inflammable principle, both of which have since been verified. Newton's treatise was not published till 1704; but it appears that part of it was composed and read to the Royal Society in the year 1675, nearly 20 years before the Florentine experiments were made.

But nearly 70 years before this latter period, Boetius de Boodt, in his History of Stones, appears to have been perfectly satisfied, from an experiment which he describes, that the diamond was of an inflammable nature. This document, which we presume will gratify the curiosity of many of our readers, is tooingular to be omitted. "Matix deinde caliciferi parum, quemadmodum et adamas debet, idque, ut impositus de supra positus maficii statim illi unionem vera unitur, ae vivos undique radios a se jaceat. Hane unionem responuit aliae omnes gemmeae diaphanæ—cur vero legitimum adamas folus tincturam illam recipiat, aliae gemme non, difficile est scire. Exstitimo mutuum illum et amicum amplexum propter similitudinem aliquam quam habent in materia, et qualitatibus; hoc est, tota utriusque natura fieri, quod itaque matix que igneæ nature ad amanti facile jungi posset, signum efi; id propter materie similitudinem fieri, ae adamantis materiam igneum, et fulphureum effe, atque ipsius humidum intrinsecum et primumgenium cujus beneficio coagulatus est, plane fusile olefum et igneum, aliarum vero gemmarum aequum.—Non mirum itaque si pinguis, oleo, et igne maficiis subtantia illi abique vivus termino adpingi et applicari, aliis vero gemmis non posset." Boetius de Boodt, Gem. et Lapid. Hist. Hanover, 1609. 4to. lib. ii. cap. i.

For the sake of the English reader we shall translate this curious document. "If mafich and the diamond be exposed to heat, and brought into contact, they enter into perfect union, and emit a very lively flame, which does not take place in any other gem. But what is the reason that the diamond alone possesses this property? I am of opinion that this mutual combination arises from a certain resemblance which each of the substances possesses in its nature and properties: on this account, therefore, the mafich, which is of a combustible nature, may be united to the diamond from a similarity in their nature, which shows that the diamond is composed of combustible and sulphurous matter; and that the humid and original particles of its composition, by means of which it was coagulated, or assumed a solid form, have been decidedly of an oily and inflammable nature, while those of other gems have been of an aqueous nature. It is not, therefore, surprising that the fat, oily, and combustible substance of mafich may enter into intimate union with the diamond, but cannot be combined with other gems."

Localities, &c.—The diamond is found in various places of the East Indies, as in the provinces of Golconda and Vizapour, in the peninsula of Hither India; and in the kingdoms of Pegu and Siam, in the peninsula of Farther India, and nearly, it is observed, in the same degree of latitude. In 1728 the diamond was discovered in Brazil, in the district of Serro-do-Frio, which is situated in the same southern latitude as the countries which produce the diamond on the north side of the equator. The native repository of the diamond, so far as is known, is a ferruginous soil, but whether it be produced on the spot where it is discovered, or have been transported from the place of its origin, has not been ascertained. It is found also in veins filled with soil of a similar nature. We shall here add a short history of the diamond mines.

The diamond mines are found only in the kingdoms of Golconda, Vizapour, Bengal, the island of Borneo, and Brazil. There are four or five mines, or rather three mines and two rivers, whence diamonds are obtained. The mines are, 1. That of Raolconda, in the province of Carnatic, five days journey from Golconda, and eight from Vizapour. It has been discovered about 200 years ago by a peasant, who digging in the ground found a natural fragment of 25 carats. 2. That of Gani, or Couleur, seven days journey from Golconda eastward. It was discovered 150 years ago by a peasant, who digging in the ground found a natural fragment of 25 carats. 3. That of Soumelpour, a large town in the kingdom of Bengal, near the Diamond-mine. This is the most ancient of all; it should rather be called that of Gonal, which is the name of the river, in the sand whereof these stones are found. 4. The fourth mine, or rather the second river, is that of Succudan, in the island of Borneo; and, 5. That of Serro-do-Frio in Brazil.

Diamond-mine of Raolconda.—In the neighbourhood of this mine the earth is sandy, and full of rocks and copse-wood. In these rocks are found several little veins of half and sometimes a whole inch broad, out of which the miners, with a kind of hooked irons, draw the sand or earth wherein the diamonds are; breaking the rocks when the vein terminates, that the track may be found again, and continued. When a sufficient quantity of earth or sand is drawn forth, they wash it two or three times, to separate the stones. The miners work quite naked, except a thin linen cloth before them; and besides this precaution, have likewise inspectors, to prevent their concealing diamonds, which, however, they frequently find means to do, by watching opportunities when they are not observed, and swallowing them.

Diamond-mine of Gani or Couleur.—In this mine are found a great number of diamonds from 10 to 40 carats, and even more. It was here that the famous diamond of the Great Mogul, which before it was cut weighed 793 carats, was found. The diamonds of this mine are not very clear; their water is usually tinged with the quality of the soil; being black where that is marly, red where it partakes of red, sometimes green and yellow, if the ground happen to be of those colours. Another defect of some consequence is a kind of greasiness appearing on the diamond, when cut, which takes off part of its lustre.—There are usually no less than 60,000 persons employed in this mine.

When the miners have found a place where they intend to dig, they level another somewhat bigger in the neighbourhood thereof, and inclose it with walls about two feet high, only leaving apertures from space to space, to give passage to the water. After a few superstitious ceremonies, and a kind of feast which the master of the mine makes for the workmen, to encourage them, every one goes to his business, the men digging the earth in the place first discovered, and the women and children carrying it off into the other walled round. They dig a few feet deep, and till such time as they find water. Then they cease digging; and the water thus found serves to wash the earth two or three times, after which it is let out at an aperture reserved for that end. This earth being well washed, and well dried, they sift it in a kind of open sieve, and lastly, search it well with the hands to find the diamonds. This mine is in a plain of about one league and a half in extent, bounded on one side by a river, and on the other by a range of lofty mountains, which form a semicircle. It is said that the nearer the digging is carried to the mountains, the diamonds are the larger.

Diamond-mine of Soumelpour, or river Goual.—Soumelpour is a considerable town near the river Goual, which runs into the Ganges. It is from this river that all our fine diamond points, or sparks, called natural sparks, are brought. They never begin to seek for diamonds in this river till after the great rains are over, that is, after the month of December; and they usually even wait till the water is grown clear, which is not before January. The season at hand, eight or ten thousand persons, of all ages and sexes, come out of Soumelpour and the neighbouring villages. The most experienced among them search and examine the land of the river, and particularly where it is mixed with pyrites, going from Soumelpour to the very mountain whence it springs. When all the sand of the river, which at that time is very low, has been well examined, they proceed to take up that wherein they judge diamonds likely to be found; which is done after the following manner: They dam the place round with stones, earth, and fascines, and throwing out the water, dig about two feet deep; the sand thus got is carried into a place walled round on the bank of the river. The rest is performed after the same manner as at other mines.

Diamond-mine in the island of Borneo, or river of Succudan.—We are but little acquainted with this mine; strangers being prohibited from having access to it; though very fine diamonds have been brought to Batavia by stealth. They were formerly imagined to be softer than those of the other mines; but experience shows they are in no respect inferior.

Diamond-mine of Serro-do-Frio.—A description of this mine was given by D’Andrada in 1792, to the Natural History Society of Paris. The mine is situated to the north of Villa Rica, in the 18th degree of south latitude. The whole country in which the diamonds are found abounds with ores of iron; and the stratum of soil, immediately under the vegetable soil, contains diamonds disseminated in it, and attached to a gaugue or matrix which is more or less ferruginous; but they are never found in veins.

When this mine was first discovered, the searching for diamonds was so successful, that the Portuguese fleet which arrived from Rio de Janeiro in 1730 brought no less than 1146 ounces of diamonds. This unusual quantity introduced into the market immediately reduced the price; and to prevent this circumstance recurring, the Portuguese government determined to limit the number of men employed in the mines.

As the diamond is the hardest of all substances, it can only be cut and polished by itself. To bring it cutting and to that perfection which augments its price so considerably, the lapidaries begin by rubbing several against each other, while rough; after having first glued them to the ends of two wooden blocks, thick enough to be held. held in the hand. It is this powder thus rubbed off the stones, and received in a little box for the purpose, that serves to grind and polish them.

Diamonds are cut and polished by means of a mill, which turns a wheel of soft iron sprinkled over with diamond-dust mixed with oil of olives. The same dust, well ground, and diluted with water and vinegar, is used in the sawing of diamonds; which is performed with an iron or brass wire, as fine as a hair. Sometimes, in lieu of sawing the diamonds, they cleave them, especially if there be any large flaws in them.

The method of cutting and polishing the diamond was not discovered till the 15th century. The diamonds which were employed as ornaments before that period, were in their rough and natural state. The invention is ascribed to Louis Berguen, a native of Bruges, who in the year 1476, cut the fine diamond of Charles the Bald, duke of Burgundy, which he lost the same year at the battle of Morat. This diamond was then sold for a crown, but afterwards came into the possession of the duke of Florence.

The first water in diamonds means the greatest purity and perfection of their complexion, which ought to be that of the purest water. When diamonds fall short of this perfection, they are said to be of the second or third water, &c. till the stone may be properly called a coloured one.

The value of diamonds is estimated by Mr Jefferies by the following rule. He first supposes the value of a rough diamond to be settled at £1 per carat, at a medium; then to find the value of diamonds of greater weights, multiply the square of their weight by 2, and the product is the value required. E.g., to find the value of a rough diamond of two carats: \(2 \times 2 = 4\), the square of the weight; which, multiplied by two, gives £8. the true value of a rough diamond of two carats. For finding the value of manufactured diamonds, he supposes half their weight to be lost in manufacturing them; and therefore, to find their value, we must multiply the square of double their weight by 2, which will give their true value in pounds. Thus, to find the value of a wrought diamond weighing two carats; we first find the square of double the weight, viz. \(4 \times 4 = 16\); then \(16 \times 2 = 32\). So that the true value of a wrought diamond of two carats is £32. On these principles Mr Jefferies has constructed tables of the price of diamonds from 1 to 100 carats.

The greatest diamond ever known in the world is one belonging to the king of Portugal, which was found in Brazil. It is still uncut; and Mr Magellan informs us, that it was of a larger size; but a piece was cleaved or broken off by the ignorant countryman, who chanced to find this great gem, and tried its hardness by the stroke of a large hammer upon the anvil.

This prodigious diamond weighs 1680 carats; and although it is uncut, Mr Romé de l'Isle says, that it is valued at 224 millions sterling; which gives the estimation of 79,36 or about 80 pounds sterling for each carat; viz. for the multiplicand of the square of its whole weight. But even in case of any error of the press in this valuation, if we employ the general rule above mentioned, this great gem must be worth at least 5,644,800 pounds sterling, which are the product of 1680 by two pounds, viz., much above five millions and a half sterling. But this gem is supposed by some to be a white topaz.

The famous diamond which adorns the sceptre of the empress of Russia under the eagle at the top of it, weighs 779 carats, and is worth at least 4,854,728 pounds sterling, although it hardly cost 135,417 guineas. This diamond was one of the eyes of a Malarian idol, named Scharingham. A French grenadier, who had deserted from the Indian service, contrived to sell as to become one of the priests of that idol, from which he had the opportunity to steal its eye: he run away to the English at Trichinopoly, and thence to Madras. A ship-captain bought it for twenty thousand rupees: afterwards a Jew gave seventeen or eighteen thousand pounds sterling for it: at last a Greek merchant named Gregory Suffrat, offered it to sale at Amsterdam in the year 1766: and Prince Orloff made this acquisition for his sovereign the empress of Russia. This diamond is of a flattened oval form and of the size of a pigeon's egg.

The diamond of the Great Mogul is cut in rose; weighs 279½ carats, and it is worth 380,000 guineas. This diamond has a small flaw underneath near the bottom: and Tavernier, page 389, who examined it, valued the carat at 150 French livres. Before this diamond was cut, it weighed 793½ carats, according to Romé de l'Isle—but Tavernier, page 339, of his second volume, says that it weighed 900 carats before it was cut. If this be the very same diamond, its loss by being cut was very extraordinary.

Another diamond of the king of Portugal, which weighs 215 carats, is extremely fine, and is worth at least 369,800 guineas.

The diamond of the grand duke of Tuscany, now of the emperor of Germany, weighs 139½ carats; and is worth at least 109,520 guineas. Tavernier says, that this diamond has a little hue of a citron colour; and he valued it at 135 livres tournois the carat. Robert de Berquen says, that this diamond was cut into two: that the grand Turk had another of the same size: and that there were at Bismarck two large diamonds, one of 250 and another of 140 carats.

The diamond of the late king of France, called the Pitt or Regent, weighs 136½ carats: this gem is worth at least 208,333 guineas, although it did not cost above the half of this sum. Patrin says, that it is believed to be at Berlin, (1. 226.) and we may add, that it has probably been carried back to France among other spoils.

The other diamond of the same monarch, called the Sancy, weighs 55 carats; it cost 25,000 guineas: and Mr Dutens says, that it is worth much above that price.

Brilliant DIAMOND, is that cut in faces both at top and bottom; and whole table, or principal face at top, is flat. To make a complete square brilliant, if the rough diamond be not found of a square figure, it must be made so; and if the work is perfectly executed, the length of the axis will be equal to the side of the square base of the pyramid.—Jewellers then form the table and collet by dividing the block, or length of the axis, into 18 parts. They take \( \frac{1}{18} \) from the upper part, and \( \frac{7}{18} \) from the lower. This gives a plane at \( \frac{1}{18} \) distance from the girdle for the table; and a smaller plane at \( \frac{5}{18} \) distance for the collet; the breadth of which will be II. Genus. ZIRCON.

1. Species. Zircon.

Jargon, Kirw. I. 257. Zircon, Haüy, II. 465. Id. Brochant, I. 159.

Effem. Char.—Its specific gravity about 4.4; the joints natural, some of which are parallel, and others are oblique to the axis of the crystals.

Exter. Char.—Colours reddish and yellowish, greenish, greenish yellow, and whitish. The colour in general varies from green to gray, and is most commonly pale; and the polished stone exhibits in some degree the play of colours of the diamond.

It is found in rounded, angular, or flattened grains, or in small angular fragments with notched edges, and also crystallized. The primitive form is an octahedron with isosceles triangles, and the integrant molecule is an irregular tetrahedron. The following are the most common forms of its crystals:

1. A prism with four rectangular faces, each base of which has a pyramid with four faces placed on the four lateral faces, which terminates sometimes in a line, but most frequently in a point.

2. The preceding crystal, in which the opposite lateral edges of the prism are truncated.

3. The crystal (1.) in which the edges of the faces of the pyramid are bevelled.

4. The crystal (1.) having the lateral edges of the prism, and the summit of the pyramid truncated.

5. The crystal (1.) in which the angles between the prism and the pyramid are bevelled.

6. A prism with four faces, having the two opposite narrow, and the two others broad.

7. A double pyramid with four faces, with the edges of the common base truncated.

8. The perfect octahedron with obtuse angles.

The crystals are commonly small; the surface smooth, but that of the angular fragments is rough. Lustre, 3 and 4; internal lustre, 4 and 3; somewhat vitreous, or approaching to that of the diamond. Fracture imperfect or flat conchoidal; fragments, 3. Transparency, 4, 3. Causes double refraction. Hardness, 9; brittle. Spec. grav. 4.416 to 4.4700.

Chem. Char.—Infusible by the blow-pipe without addition, but with borax it forms a transparent colourless glass. The following are its constituent parts.

| Constituent Parts | |------------------| | From Ceylon. | | Zirconia, | 70 | | Silica, | 26 | | Iron, | 1 | | Lofs, | 3 | | | 100 |

Localities.—The zircon was first found in Ceylon, accompanied with crystals of spinel and tourmaline, in a river near the middle of the island; and more lately it has been found in Norway, in a rock composed of feldspar and hornblende.

Uses.—The zircon is employed as a precious stone, and particularly as an ornament in mourning.

2. Species. HYACINTH.

Id. Kirw. I. 257. Zircon, Haüy, II. 465. L'Hyacinthe, Brochant, I. 163.

Effem. Char.—The same as the first species.

Exter. Char.—The most common colour is what is called hyacinth red, blood red, and yellowish brown.

It is found in rounded grains, and frequently in crystals, the primitive form of which is the same as the first species. The crystals are,

1. A prism with four faces. 2. The same slightly truncated on its edges. 3. The double pyramid with four faces, or a very obtuse octahedron, which is a rare variety. 4. A prism with five faces, each base of which is terminated by an acumination with three faces, placed alternately on the three lateral edges, forming the rhombohedral dodecahedron.

The crystals are commonly small, the surface smooth; external lustre, 3, 4; internal, 4, 5; greasy; fracture straight foliated; cleavage double, rectangular; fragments, 3; transparency, 4, 2; causes double refraction; hard and brittle; unctuous to the touch when cut; spec. grav. 4.385 to 4.620.

Chem. Char.—By the action of the blow-pipe the hyacinth loses its colour, but retains its transparency. It is infusible without borax, which converts it into a transparent colourless glass.

| Constituent Parts | |------------------| | From Expaille. | | Zirconia, | 70 | | Silica, | 25 | | Oxide of iron, | 0.5 | | Lofs, | 4.5 | | | 100 Klap.|

Localities.—It is found in Ceylon in similar situations with the former; in Brazil, Bohemia, and in the rivulet Expaille, in Velay in France; and also in the neighbourhood of Pisa in Italy.

Uses.—As it is susceptible of a fine polish, the hyacinth has been ranked among precious stones.

Remarks.—The analogy between the crystalline forms of the zircon and hyacinth; their double refraction; the similarity of their other characters, and particularly the results of chemical analysis, have led Haüy to form them into one species.

A variety, under the name of cinnamon stone, has been considered as a distinct species; but the differences are so very slight, that it may be included in the description of the preceding.

III. Genus. SILICEOUS.

1. Species. CHRYSOBERYL.

Id. Emm. Wid. Lenz. Kirw. Chrysopale, Lam. Cyphomane, Haüy.

Exter. Char.—The colour is an asparagus green; paling passing sometimes to a greenish white, and sometimes to an olive green; sometimes bright brown and yellowish brown, passing to yellowish gray; affords a feeble change of colour from bluish to milky white.

It is found in angular or rounded grains, which appear to have been water worn; and in crystals, exhibiting, 1. A table with six faces, elongated, of various thicknesses, truncated on the terminal edges. 2. A prism with four rectangular faces. 3. A prism with six faces, of which four are broader and two are narrower opposite to each other.

The grains are slightly rough, and have a considerable external lustre. The crystals are striated lengthwise on their lateral faces; the other faces are smooth; lustre external very shining—internal the same, intermediate between that of the diamond and the vitreous lustre.

The fracture is in all directions perfectly conchoidal; the fragments are indeterminate with sharp edges. It has little transparency, but a considerable degree of hardness. Spec. grav. 3.698 to 3.719 Wern. 3.710 Klap. 3.796 Haüy.

Chem. Char.—It is infusible without addition by the action of the blow-pipe. By Klaproth’s analysis, the following are its constituent parts.

| Alumina, | 71.5 | | Silica, | 18 | | Lime, | 6 | | Oxide of iron, | 1.5 | | Lofs, | 3 |

Locality.—Brazil, Ceylon, Siberia.

Uses.—The hardness of the chrysoberyl, and change of colour which it exhibits, have procured it a place among precious stones of inferior value. It is known in commerce under the name of changeable opal or oriental chrysoberyl.

2. Species. CHRYSOLITE.

Id. Emm. Wid. Lenz. Muf. Lebk. Kirw. Peridot, Daub. Haüy.

Exter. Char.—The most common colour is a bright pistachio green, passing to an olive green; sometimes of a bright asparagus or clear meadow green; rarely the green approaches to brown and almost to a cherry red.

It is found in angular fragments with the edges a little notched, or in rounded grains, or in crystals having the angles and edges a little notched. The forms of its crystals are, 1. A large rectangular prism having its lateral edges truncated and sometimes bevelled, and terminated by a six-sided prism, of which two opposite sides are placed on the small lateral faces of the prism. The four others on the lateral truncated faces, the latter forming a more acute angle than the two former.

2. The next form varies from the preceding, in having two additional terminating faces, placed on the broad faces of the prism, each of which is consequently situated between two of the planes corresponding to the truncated planes.

3. In another variety the summit of the pyramid is truncated by a convex cylindrical plane, the convexity of which passes from one of the small opposite lateral planes towards the other.

4. In some instances the crystals are so small, that the small lateral faces almost entirely disappear, while the two larger assume a curved form, giving such crystals a tabular appearance.

The external surface of the angular fragments and of the rounded crystals is scaly, which affords an essential character to this mineral. The small lateral planes are smooth, the broad ones are distinctly striated lengthwise. Externally the surface is shining; internally shining and vitreous.

The fracture in all directions is perfectly conchoidal; the form of the fragments is indeterminate, with very sharp edges. It is almost always transparent, and refracts double; it is not so hard as quartz. Brittle. Spec. grav. 3.340 to 3.420 Wern. 3.428 Haüy.

Chem. Char.—By the action of the blow-pipe it is fused with borax without effervescence, and affords a greenish, transparent glass.

Constituent parts.

| Silica, | Crystallised. | Cut. | Crystallised. | |--------|--------------|------|--------------| | | 38 | 39 | 38 | | Magnesia, | 39.5 | 43.5 | 50.5 | | Oxide of iron, | 19. | 19 | 9.5 | | Lofs, | 3.5 | | 2. |

Locality, &c.—This mineral is brought from the Levant, but it is not known whether it is found in Asia or Africa. It has been discovered in Bohemia; and crystallised specimens included in a kind of lava, have been brought from the island of Bourbon. As it is usually found in rounded fragments, in the midst of earthy substances, its relative situation is scarcely known.

Uses.—The chrysoberyl has been often employed for various purposes as a precious stone, but as it possesses no great degree of hardness, it is not much esteemed.

Substances of a very different nature have been, at different times, described under the name of Chrysoberyl. It appears that the yellow chrysoberyl of the ancients is the same with our topaz, and that their green topaz is our chrysoberyl. Plin. lib. xxxvii. cap. 8.

3. Species. OLIVINE.

Id. Emm. Wid. Lenz. Kirw. Lameth. Chrysoberyl en grains irréguliers, De Born. Peridot Granuliforme, Haüy. Chrysoberyl des Volcans, of many mineralogists.

Exter. Char.—The most common colour is a bright olive green, sometimes of an apple green, pistachio, or mountain green; a wine, honey, or orange yellow, and sometimes also a reddish brown, and brownish black; but these latter varieties are rare. It is found in rounded pieces, from the size of the head to that of a grain of millet, most commonly included, and disseminated in basalt. It has been found crystallized.

Internally, Internally, this mineral varies in its lustre between shining and weakly shining; in the yellow varieties the lustre is between vitreous and resinous.

The fracture is more or less conchoidal; sometimes uneven; the shape of the fragments is indeterminate, with sharp edges. The rounded pieces of a certain size are composed of distinct granular concretions, with small grains.

It is sometimes transparent, and varies to semitransparent and translucence. It is brittle and not so hard as quartz. Spec. grav. 3.225 to 3.265.

Chem. Char.—Olivine is infusible by the action of the blow-pipe; in nitric acid it loses its colour, giving to the liquid a pale yellow colour.

| Constituent Parts | Klaproth | |------------------|---------| | Silica | 48 | | Magnesia | 37 | | Lime | 0.25 | | Oxide of iron | 12.5 | | Lofs | 2.25 |

Locality, &c.—Olivine is found in different countries, as in Bohemia and Saxony, and in Vivarais in France, and most commonly in rounded pieces in the cavities of basalt. Brochant says that it has not been discovered in the basalts of Ireland, England, Sweden, Norway, and Italy. We have, however, collected specimens of olivine among the basaltic rocks of the Giant's Causeway in Ireland.

Olivine and chrysolite are considered by Hauy as one species, and described under the name peridot.

4. Species. COCCOLITE.

Coccolithe, Brochant, ii. 504. Hauy, iv. 355. D'Andrada. Nich. 4to. Jour. v. 495.

Exter. Char.—Colour, meadow green, olive, or blackish green. It is found in masses which are composed of separate pieces, granular, in small grains, which may be easily separated; these grains are angular, and discover some appearance of tendency to crystallization.

Lustre, resplendent, vitreous; fracture foliated; cleavage double, as examined by Hauy, but single according to D'Andrada: it is hard, scratches glass; the grains are often translucent. Spec. grav. 3.316 to 3.373.

Chem. Char.—Coccolite is infusible without addition before the blow-pipe. With borax it melts into a pale yellow transparent glass, and with carbonate of potash into an olive green vesicular glass.

| Constituent Parts | |-------------------| | Silica | 50.0 | | Lime | 24.0 | | Magnesia | 10.0 | | Oxide of iron | 7.0 | | Oxide of manganese| 3.0 | | Alumina | 1.5 | | Lofs | 4.5 |

Locality, &c.—Augite is found in basalt along with olivine and hornblende, in Bohemia, Hungary, and Transylvania; in the basalt of Arthur's seat near Edinburgh.

6. Species. VESUVIAN.

La Vesuvienne, Brochant, i. 184. Idocrase, Hauy, ii. 574.

Effem. Char.—Divisible, parallel to the faces and diagonals of a rectangular prism, with square bases; melts into a yellow glass.

Exter. Char.—Colour brown, orange, dark green, and yellowish green.

This mineral is found massive, disseminated, or crystallized. Primitive form, a rectangular prism, little different from a cube; integrant molecule a triangular prism. The forms of its crystals are, a rectangular prism, with four sides, truncated on all its edges, or truncated on its lateral edges; or a six-sided prism, truncated on all its edges. The crystals are usually small, single sometimes, and sometimes in groups. Lateral planes longitudinally streaked. Some are smooth; smooth; lustre resplendent, vitreous; internal lustre shining, resinous. Fracture imperfectly conchoidal, sometimes uneven, often also foliated. Fragments indeterminate, with rather sharp edges. Translucent, and almost semitransparent; hard, brittle; specific gravity 3.365 to 3.420.

Chem. Char.—Fusible without addition into a yellow glass.

Constituent Parts, Klaproth.

| From Vesuvius | From Siberia | |---------------|-------------| | Silica | 35.50 | 42 | | Lime | 33. | 34 | | Alumina | 22.25 | 16.25 | | Oxide of iron | 7.5 | 5.5 | | Oxide of manganese | .25 | atom |

Localities, &c.—It is found in the neighbourhood of Vesuvius, accompanied by limestone in small grains, feldspar, mica, hornblende, and calcareous spar; and it is supposed to have been thrown out of the volcano unchanged. In Siberia it is found in steatites, sometimes mixed with crystals of magnetic iron.

Uses.—At Naples it is employed as a precious stone.

7. Species. Leucite.

La Leucite, Brochant, i. 188. Vesuvian, Kirwan, i. 285. Amphigene, Haüy, ii. 539.

Effem. Char.—Divisible, parallel to the faces of a cube, and at the same time to those of a rhomboidal dodecahedron.

Exter. Char.—Colour grayish or yellow white.

It is rarely found massive or in grains, but most frequently crystallized. The primitive form of its crystals is the cube; the integrant molecule an irregular tetrahedron; the most common form of the crystals is a short double pyramid with eight faces opposed base to base, each summit of which is surmounted by an obtuse acummation with four faces, corresponding alternately to the four lateral edges of the pyramid, and thus producing a figure of twenty-four trapezoidal faces; the crystals are commonly small, the surface rough and dull, or at most feebly shining. Internal lustre shining, vitreous. Fracture foliated, sometimes conchoidal. Fragments indeterminate with sharp edges. Semitransparent or translucent. Scarcely scratches glass. Brittle. Spec. grav. 2.455 to 2.490.

Chem. Char.—Insoluble before the blow-pipe, but with borax gives a transparent glass.

Constituent Parts.

| Klaproth | Vauquelin | |----------|-----------| | Silica | 54 | 56 | | Alumina | 24 | 20 | | Potash | 21 | 20 | | Lime | | 2 | | Lofs | 1 | 2 |

Localities, &c.—Leucite is found in the lavas of Vesuvius, and in the basalts of Italy; in basalts and other rocks of Bohemia, and also, it is said, in a granitic rock in the Pyrenees.

8. Species. Melanite, or Black Garnet.

La Melanite, Brochant, i. 191.

Exter. Char.—Colour velvet black, or brownish or grayish black. It is most commonly found crystallized, in fixed prisms, terminated at each extremity by an obtuse acummation, with three planes placed alternately on three of the lateral edges; the prisms are sometimes truncated on all the edges, and sometimes only the lateral edges. The surface is smooth and shining. Internal lustre shining. Fracture imperfect, flat, conchoidal. Fragments indeterminate, sharp-edged, opaque, hard, and rather brittle. Spec. grav. 3.691 to 3.800.

Constituent Parts, Vauquelin.

| Silica | Alumina | Lime | Oxide of iron and of manganese | Lofs | |--------|---------|------|------------------------------|-----| | 35 | 6 | 32 | 25 | 2 |

Localities.—It has been found only at Frosinone and St Albano near Rome.

9. Species. Garnet.

Le Grenat, Brochant, i. 193. Garnet, Kirwan, i. 238. Grenat, Haüy, ii. 540.

Effem. Char.—Specific gravity at least 3.5. The forms derived from the rhomboidal dodecahedron.

The primitive form is a rhomboidal dodecahedron. The inclination of each rhomb to the two adjacent is 120°, the plain angles 120° 28' 16" and 70° 31' 44". The integrant molecule is the tetrahedron, whose faces are isosceles triangles equal and similar.

The garnet is divided into three subspecies, the precious, common, and Bohemian garnet.

Subspecies 1. Precious Garnet.

Exter. Char.—Colour red, of which there are several varieties, as blood red, cherry red, hyacinth red, sometimes brown and even black.

The garnet is rarely found massive or disseminated, but sometimes in rounded grains, and most frequently crystallized, of which the following are the forms.

1. A prism with six sides terminated by a double obtuse summit with three faces, corresponding alternately to the three lateral edges at each end of the prism, and thus forming a rhomboid of twelve faces.

2. The same crystal truncated on all its edges, forming a figure of 36 faces. The faces of the truncations are elongated hexagons.

3. A short double pyramid, with eight faces opposed base to base, the summits of each of which are surmounted by an obtuse acummation, corresponding alternately to the four lateral edges of one of the pyramids, mids, forming a crystal of 24 sides, which are pretty equal trapezoids.

4. The preceding form with twelve truncations; eight on the eight acute alternating angles of the two summits, and four on the obtuse angles of the common base of the two pyramids, making in all 36 faces.

The surface is a little unequal in the grains, smooth in the crystals, and almost always streaked diagonally. The lustre varies from thinning to resplendent, and is vitreous. Fracture more or less perfectly conchoidal, sometimes uneven or splintery, and sometimes foliated. Fragments indeterminate with sharp edges. Transparent or translucent. Scratches quartz. Refraction simple. Brittle. Spec. grav. 4.085 to 4.352.

Chem. Char.—Before the blow-pipe it is fusible into a dark enamel.

**Constituent Parts.**

| | Klaproth. | Vauquelin. | |----------------|-----------|------------| | Silica | 35.75 | 36 | | Alumina | 27.25 | 22 | | Lime | | 3 | | Oxide of iron | 36 | 41 | | Oxide of manganese | .25 | - | | Lofs | .75 | - |

100.00 102

**Localities, &c.**—The garnet is not uncommon in most countries of the world, and it is usually found in primitive rocks.

*Ufer.*—It is employed as a precious stone.

The precious garnet is supposed to be the carbuncle of the ancients.

**Subspecies 2. Common Garnet.**

*Effem. Char.*—The same as the precious garnet.

*Exter. Char.*—It is found massive and disseminated, and also sometimes crystallized. The forms of the crystals are the same as those of precious garnet. The surface of the crystals is diagonally streaked.

Colour brown, green, greenish black, brownish red, and orange yellow. Lustre thinning, resinous, or vitreous. Fracture uneven, sometimes splintery. Fragments sharp-edged. Rarely transparent, sometimes translucent, and commonly at the edges; not so hard as the precious garnet. Brittle. Spec. grav. from 3.668 to 3.757.

*Chem. Char.*—Melts before the blow-pipe into a dark enamel, and easier than the former.

**Constituent Parts.**

| | Black Garnet. | Yellowish Garnet. | |----------------|---------------|-------------------| | Silica | 43 | 38 | | Alumina | 16 | 20 | | Lime | 20 | 31 | | Oxide of iron | 16 | 10 | | Water | 4 | - | | Lofs | 1 | 1 |

100 100

**Localities, &c.**—The common garnet is found in micaceous schistus, gneis, serpentine, and other primitive rocks, in Saxony, Bohemia, France, Sweden.

*Ufer.*—It is rarely employed as a precious stone, but frequently as a flux for iron ores.

**Subspecies 3. Pyrope, or Bohemian Garnet.**

Pyrope, Brochant, ii. 498.

*Effem. Char.*—The same as the garnet.

*Exter. Char.*—This mineral is found in small, round angular fragments; it is never crystallized.

Colour dark blood red, which, by holding it between the eye and the light, becomes yellow. Lustre resplendent, vitreous. Fracture conchoidal. Fragments indeterminate and sharp-edged. Perfectly transparent. Scratches quartz. Spec. grav. 3.718 to 3.941.

**Constituent Parts.**

| | Klaproth. | |----------------|-----------| | Silica | 40 | | Alumina | 28.5 | | Lime | 3.5 | | Magnesia | 10 | | Oxide of iron | 16.5 | | Oxide of manganese | .25 | | Lofs | 1.25 |

100

**Localities, &c.**—This mineral is found in serpentine in Saxony; the most beautiful are from Bohemia, where it is found in alluvial land.

*Ufer.*—It is employed in jewellery. The small grains are used as a substitute for emery in polishing.

This mineral is formed into a separate type by some, and is distinguished from the garnet by its colour, want of crystallization, and transparency; but these differences in the external characters Hauy considers as insufficient to constitute a different species of two minerals which agree in a greater number of other characters. Magnesia indeed has been detected in the latter as one of its constituents, no trace of which has been yet discovered in the former.

**10. Species. Grenatite.**

Grenatite, Brochant, ii. 496. Id. Saussure, § 1900. Staurolite, Hauy, iii. 93. Pierre de Croix, De Lille, ii. 434.

*Effem. Char.*—Divisible parallel to the sides of a rhombohedral prism, whose angles are equal to $129^\circ 30'$, and $50^\circ 30'$, which may be subdivided in the direction of the short diagonals of the bases.

*Exter. Char.*—Grenatite is always found crystallized. The primitive form is a rectangular prism with rhombohedral bases, having the angles inclined, as mentioned in the essential character. The integrant molecule is a triangular prism. It is frequently met with in double crystals, crossing each other in the form of a cross, from which the name is derived, sometimes at right angles, and sometimes obliquely; sometimes also there are oblique triple crossings. The surface is smooth and shining, or uneven and dull.

The colour is reddish or blackish brown; internal lustre shining, between vitreous and resinous. Fracture imperfectly imperfectly foliated, in the direction of the axis; in other directions uneven, small grained, or sometimes a little conchoideal; often opaque, sometimes translucent. Scratches quartz feebly; specific gravity 3.2861.

Chem. Char.—Before the blow-pipe it becomes brown without fusion, and is then converted into a fritty substance.

Constituent Parts.

| Vauquelin | |-----------| | Silica, | 33 | | Alumina, | 44 | | Lime, | 3.84 | | Oxide of iron, | 13 | | Oxide of manganese, | 1 | | Loos, | 5.16 |

Localities, &c.—It is found in small crystals in micaceous schistus, at St Gothard in Switzerland, in Brittany in France, and in Spain, in primitive rocks.

II. Species. Ceylanite.

Pleonaflte, Hauy, iii. 17. Spinelle Pleonaflte, Brongniart, i. 438.

Effem Char.—Scratches glass slightly, and is divisible into a regular octahedron.

Exter. Char.—This mineral is found in rounded masses, and also crystallized. Primitive form of the crystals, a regular octahedron. The integrant molecule a regular tetrahedron. The edges of the octahedron are sometimes truncated, and form a regular 12-sided rhomboid. The crystals are small; the fracture is conchoideal; the lustre thinning and vitreous.

The colour is sometimes perfectly black, brown, bright blue, purplish red, or dark green. It is hard, but not very brittle. Spec. grav. 3.76 to 3.79.

Chem. Char.—Insoluble before the blow-pipe.

Constituent Parts. Descotils.

| Klaproth. | Vauquelin | |-----------|-----------| | Alumina, | 74.50 | 82.47 | | Silica, | 15.50 | | | Magnesia, | 8.25 | 8.78 | | Oxide of iron, | 1.50 | | | Lime, | .75 | | | Chromic acid, | 6.18 | | | Loos, | | 2.57 |

Localities, &c.—This mineral is met with in the island of Ceylon, along with tourmaline and other crystallized substances, which have been carried from their native repositories by means of water. It has been found also in disseminated crystals in the cavities of the lava of Vesuvius; and very small blue crystals of ceylanite have been observed in the volcanic (basaltic) rocks at Closterlach on the banks of the Rhine.

12. Species. Spinelle.

Spinel and Balas Ruby, Kirw. i. 253. Le Spinel, Brochant, i. 202. Spinelle, Hauy, ii. 496.

Effem Char.—Scratches quartz strongly; the primitive and common form, a regular octahedron.

Exter. Char.—Spinelle is found in rounded grains, or crystallized; the primitive form of the crystals is a regular octahedron; the integrant molecule the regular tetrahedron. Its usual forms are a double pyramid with four faces applied base to base, constituting a perfect octahedron; or it is truncated on all its edges, or only on those of the common base of the two pyramids. It is met with also in the form of a double crystal, composed of two octahedrons, which are often flattened.

Colour usually red, of various shades, from carmine red to rose red; sometimes reddish white, and orange yellow. Faces of the octahedron smooth, those of the truncations longitudinally streaked. Lustre resplendent, vitreous; fracture conchoideal; the longitudinal fracture is foliated; fragments indeterminate, sharp-edged; semiflattened, and sometimes transparent. Scratches quartz; is scratched by sapphire. Spec. grav. 3.570 to 3.645.

Chem. Char.—Before the blow-pipe it is insoluble; but with borax it melts, and without frothing up.

Constituent Parts.

| Klaproth. | Vauquelin | |-----------|-----------| | Alumina, | 74.50 | 82.47 | | Silica, | 15.50 | | | Magnesia, | 8.25 | 8.78 | | Oxide of iron, | 1.50 | | | Lime, | .75 | | | Chromic acid, | 6.18 | | | Loos, | | 2.57 |

Localities, &c.—Crystals of spinelle are found in Ceylon, in a river which comes from the high mountains in the middle of that island; they are accompanied with zircon, tourmaline, and different other stones. It is found also in Pegu.

Ufem.—Spinelle is ranked among precious stones, and is greatly esteemed when it is of a certain size. It is said that a fine spinelle ruby, whose weight exceeds four carats, is worth half the price of a diamond of the same weight.

13. Species. Sapphire.

Oriental Ruby, Sapphire, and Topaz, Kirwan, i. 250. Le Saphir, Brochant, i. 207. Teleste, Hauy, ii. 480.

Effem Char.—Specific gravity about 4; natural joints very distinct, and perpendicular to the axis of the crystals.

Exter. Char.—Sapphire is found in fragments, in rounded pieces, and also crystallized. The primitive form of the crystal, according to Hauy, is a regular six-sided prism, and the integrant molecule is a triangular, equilateral prism; but, according to Bournon, the primitive form is a rhomboid, whose angles are 90° and 84°. The usual forms of the crystals are, 1. A small six-sided prism. 2. A pyramid with five faces, very sharp, double, the two pyramids applied base to base. 3. The same crystal with the summit truncated. 4. A pyramid with five faces, double; the two pyramids applied base to base, but less sharp than the second form. The surface of the crystals is smooth, and often streaked transversely. The principal colour is blue, varying between Prussian and indigo blue; other varieties are of a deep violet blue. Sapphires are also found red, yellowish, and greenish. Two or three colours appear in the same crystal, sometimes in bands and sometimes in concentric circles. Externally, the lustre of the sapphire is thinning; internally, refulgent and vitreous. Fracture perfectly conchoidal. Fragments sharp-edged; transparent or semitransparent, sometimes only translucent. Scratches all other earthy substances. Brittle. Spec. grav. 3.901 to 4.283.

Chem. Char.—Infusible before the blow-pipe. Melts with borax without intumescence. The blue variety, exposed to a strong heat, loses its colour, Haüy.

Constituent Parts.

| Klaproth | Bergman | |----------|---------| | Alumina | 98.5 | | Silica | 9.5 | | Lime | 0.5 | | Oxide of iron | 1. |

100 100

Sapphire. Oriental Ruby.

| Alumina | 92 | |---------|---------| | Silica | 5.25 | | Oxide of iron | 1. | | Lofs | 1.75 |

100 100

Localities, &c.—The finest sapphires are brought from Pegu and the island of Ceylon. The sapphire is also found in Bohemia, accompanied with zircon, Bohemian garnet, and magnetic iron; and in the river Expally in France.

Uses.—The sapphire, next to the diamond, is the most highly valued of precious stones.

14. Species. CORUNDUM.

Corindon, Haüy, iii. i. Adamantine Spar, Kirw. i. 335. Le Spath Adamantin, Broch. i. 356.

Effen. Char.—Scratches quartz; divisible into a rhomboid somewhat acute.

Exter. Char.—This mineral is found massive, disseminated, and crystallized; 1. In six-sided prisms, having the extremities broken, and the faces sometimes unequal. 2. A six-sided prism, terminated by a six-sided pyramid. 3. A pyramid with six short faces, whose summit is strongly truncated; and, 4. The preceding crystal terminated by a three-sided pyramid. From the investigations of Count de Bourbon and Mr Greville, it appears that the crystallization of corundum is similar to that of the sapphire*. Lustre, which is intermediate between refrinous and vitreous, shining or weakly shining; cros fracture uneven or splintery, sometimes foliated; fragments rhomboideal, sometimes sharp-edged.

The colour is greenish white, greenish gray, and asparagus green, translucent at the edges; refraction double. Extremely hard. Spec. grav. 3.710 to 3.873.

Chem. Char.—Entirely infusible before the blow-pipe.

According to Chenevix.

| From the Carnatic | From Malabar | |-------------------|-------------| | Silica | 5 | | Alumina | 91 | | Oxide of iron | 1.5 | | Lofs | 2.5 |

100 100

Localities.—Corundum is found in a hard rock near the river Cavery, south of Madras; on the Malabar coast; in the island of Ceylon; in the kingdom of Ava; and in China.

15. Species. ADAMANTINE SPAR.

Exter. Char.—This mineral, which ought undoubtedly to be considered as a variety of corundum, is found massive, in rolled pieces, and crystallized in six-sided prisms, and six-sided acute pyramids with truncated extremities. Internal lustre splendid; fracture foliated; fragments rhomboideal.

Colour dark hair brown; very hard. Spec. grav. 3.981.

Constituent Parts.

| Klaproth | |----------| | Silica | | Alumina | | Oxide of iron | | Lofs |

100

Localities.—This mineral has been only met with in China.

16. Species. EMERY.

Fer Oxydé Quartzifère, Hauy, iv. 112. Emery, Kirw. ii. 193. L'Emeril, Broch. ii. 292.

Effen. Char.—The powder scratches all bodies except the diamond.

Exter. Char.—This mineral is found massive and disseminated. The lustre is glimmering or weak shining, and adamantine. Fracture fine-grained, uneven; fragments a little blunt-edged.

Colour grayish black, bluish, smoke or steel gray; generally opaque, but sometimes translucent at the edges; extremely hard. Spec. grav. about 4.

Chem. Char.—Becomes black under the blow-pipe, but is infusible. Colours borax of a dirty yellow. Constituent Parts.

| Tennant | Alumina | Silica | Oxide of iron | Lofs | |---------|---------|--------|---------------|------| | | 86 | 3 | 4 | 7 |

100 *

Localities, &c.—This mineral is found in Saxony, disseminated in a bed of indurated steatites, mixed with common talc; also in the island of Naxos in the Archipelago; and in Italy, Spain, and Peru.

Uses.—Emery, as well as the two former species, is employed, when reduced to powder, in cutting and polishing hard stones, glas, and metals.

Not only the external characters, but also the near approach in the proportion of their constituent parts, of the three species last described, would lead to consider them as the same species, or at least as varieties. Emery is by some mineralogists arranged among the ores of iron.

17. Species. Topaz.

Occidental Topaz, Kirw. i. 254. La Topaze, Broch. i. 212. Topaze, Hauy, ii. 504.

Effem. Char.—Refraction double; joints very distinct; perpendicular only to the axis of the crystals.

Exter. Char.—The topaz is sometimes found massive, sometimes disseminated, and sometimes in rounded fragments; but it is most commonly crystallized. The primitive form of its crystals is a right-angled prism, whose bases are rhombs, and having the large angle $124^\circ 22'$; the integrant molecule is the same. The most common forms of the topaz are,

1. A prism with eight sides, terminated at the one end by a four-sided summit, and at the other (which but rarely happens), by one of a different form. In a variety of the Brazilian topaz, the one summit presents five sides, and the other ten; and the electricity exhibited by the latter by means of heat, is negative, while that of the former is positive. This difference in the two opposite summits of a crystal, as has been observed by Hauy, is a peculiarity in all crystals which acquire by means of heat two kinds of electricity.

2. The next common form of the topaz is an eight-sided prism, whose base is horizontal, and bordered with a row of six oblique faces. This variety, which is found in the mines of Saxony, becomes readily electric by friction, but not by heat.

The prevailing colour of the topaz is yellow of various shades. The crystals are of middling size; their lateral faces are sometimes convex and cylindrical; the surface of the same faces is longitudinally striated, while that of the other faces is smooth. Lustre vitreous; cross fracture perfectly foliated; longitudinal fracture conchoidal; fragments indeterminate; transparent; sometimes semitransparent or translucient; refraction double; scratches rock-crystal. Spec. grav. 3.464 to 3.564.

Chem. Char.—Insoluble before the blow-pipe, but melts with borax without intumescence. The Brazilian topaz heated in a crucible assumes a rose red colour, when it is called by the jewellers ruby of Brazil. The Saxon topaz becomes white when exposed to heat; and thus deprived of colour, is sold for the diamond. According to Vauquelin, all the varieties of topaz reduced to powder, and added to syrup of violets, at the end of two or three hours communicate a green colour.

According to Klapproth and Vauquelin.

| Alumina | 47 to 50 | |---------|----------| | Silica | 28 to 30 | | Fluoric acid | 17 to 20 | | Iron | 0 to 4 |

Localities, &c.—The topaz is found in different parts of Saxony, particularly in the mountain Schneckenstein, which is denominated topaz rock, and is arranged with the primitive mountains. In this rock the topaz is mixed with quartz, felspar, mica, and lithomarga. Near Zinnwald it is found in granite. It is also found mixed with ores of tin. In Siberia the topaz is found in graphic granite, accompanied with beryl, quartz, and garnet. Topaz is also met with in Brazil and Asia Minor.

Uses.—The topaz is employed for the purposes of jewellery as a precious stone, but it is not considered of very great value.

18. Species. Pyrophysalite.

This mineral which was described and analysed by Hisinger and Berzelius, is of a greenish white colour. When thrown on hot coals it becomes phosphorescent, and gives out a greenish flame. When it is strongly heated by the action of the blow-pipe, the surface is covered with small vesicles which explode. These phenomena are ascribed to the fluate of lime which forms one of its constituent parts, and which sometimes appears surrounding it with a crust.

Localities, &c.—Gahn found this stone at Finbo near Falun in Sweden, in nodules imbedded in a granite, composed of white quartz, feldspar, and silvery mica. The nodules are separated from the rock by a greenish yellow talc.

19. Species. Euclase.

Id. Hauy, ii. 531. Id. Brochant, ii. 308.

Effem. Char.—Divisible by two longitudinal lines perpendicular to each other.

Exter. Char.—This mineral has only been found crystallized. The primitive form of the crystals is a rectangular prism with square bases, and that of the integrant molecule is the same. The most common form under which it appears is an oblique four-sided prism, with the edges truncated in various ways. The crystals are streaked longitudinally. The lustre is dependent and vitreous. Longitudinal fracture foliated; cross fracture conchoidal.

Colour, bright sea green. Transparent, and refracts double. Scratches quartz. Very frangible; hence its name signifying easily broken. Spec. grav. 3.062.

Chem. Char.—Loses its transparency before the blow-pipe, and melts into a white enamel. Localities.—This mineral was brought from Peru, and has never been found anywhere else. It was in single crystals, so that its repository is unknown. It is by some mineralogists arranged among the ores of iron.

20. Species. EMERALD.

Id. Kirw. i. 247. L'Emeraude, Brochant, i. 217. Emeraude, Hauy. ii. 516.

Effem. Char.—Scratches glass easily; divisible, parallel to the faces, and to the bases of a regular hexahedral prism.

Exter. Char.—The emerald is only found crystallized, and the primitive form of its crystals is a regular six-sided prism; the integrant molecule is a triangular prism, the sides square, and the bases equilateral triangles. The usual forms are, 1. A perfect six-sided prism; 2. Truncated on its lateral edges; 3. Truncated on its terminal edges; 4. Truncated on its terminal angles; and, 5. Having the terminal edges bevelled. The crystals are seldom large. Their surface is smooth and shining; internal lustre shining and resplendent; vitreous; fracture conchoidal or unequal, sometimes transversely foliated; fragments indeterminate, sharp-edged.

Colour emerald green of all shades; most commonly transparent, sometimes only translucent; refraction double; with difficulty scratches quartz. Spec. grav. 2.600 to 2.775.

Chem. Char.—Fusible before the blow-pipe, but with difficulty; melts readily with borax.

Constituent Parts.

| Vauquelin | Klaproth | |-----------|----------| | Silica | 64.50 | 68.50 | | Alumina | 16 | 15.75 | | Glucina | 13 | 12.50 | | Oxide of chromium | 3.25 | .30 | | Lime | 1.60 | .25 | | Oxide of iron | 1 | | | Water | 2 | |

Localities, &c.—The finest emeralds are brought from Peru, where they are found in veins or cavities of the granite mountains. They are also found in Upper Egypt, Ethiopia, and in the island of Ceylon. The emerald is accompanied by calcareous substances, as carbonate of lime and gypsum.

Uses.—The rich green of the emerald has obtained for it a high rank among precious stones, and it is employed for similar purposes.

21. Species. BERYL.

Aqua Marina et Samaragdus, Berylus, Wallerius, i. 254. Aigue Marine de Siberie, Romé de Lisle, ii. 252. Id. De Born, i. 71. Beryl, Kirw. i. 248. Le Beril Noble, Brochant, i. 220. Emeraude Limpide, vert-bleuclaire, jaune-verdatre, &c. Hauy, ii. 521.

Effem. Char.—The same as the emerald.

Exter. Char.—The beryl is sometimes found in rounded fragments, but most commonly crystallized, and the forms of its crystal are the same as the emerald. The lateral faces of the crystals are deeply striated.

The colours of the beryl are usually a pale or yellowish green; external lustre shining; internal resplendent, vitreous; longitudinal fracture conchoidal, or foliated. Cleavage fourfold. Fragments indeterminate and sharp-edged; often transparent, sometimes semi-transparent, and translucent. The latter variety is distinguished by transverse rents. Refraction in a slight degree double; nearly as hard as topaz; brittle; spec. grav. 2.65 to 2.75. Becomes electric by friction.

Chem. Char.—Before the blow-pipe it is fusible, but with difficulty, and yields a white, scarcely translucent glass.

Constituent Parts.

| Vauquelin | Rose | |-----------|------| | Silica | 68 | 69 | | Alumina | 15 | 14 | | Glucina | 14 | 14 | | Lime | 2 | | | Oxide of iron | 1 | |

Localities, &c.—The beryl is brought from the East Indies, and from Brazil; but the finest and purest are found in Dauria, on the frontiers of China, in the neighbourhood of Nertschink; and the matrix of these beryls is said to be an indurated clay, resembling jasper. The beryl is also found in Siberia, where it is usually accompanied with quartz, feldspar, garnets, tourmaline, mica, and fluor spar, in the veins of primitive mountains. The beryls from Siberia are almost all found in graphic granite. Beryl is also found in Saxony, and lately in France, in a large vein of quartz traversing graphic granite. Dolomieu found the beryl perfectly transparent and colourless, in the granite of the island of Elba.

Uses.—The beryl is employed as a precious stone, but is not greatly esteemed.

Remarks.—The emerald and the precious beryl approach so nearly to each other, not only in the forms of their crystals, which are almost the same, and in their constituent parts, which afford but slight variations, but also in their other characters, that they ought to be considered, as has been done by Hauy, as varieties of the same species. The only differences which exist between them seem to be accidental. There are chiefly in the colour, and in the crystallization; the former of which is a finer green, and the latter is more perfect in the emerald than in the beryl. The colouring matter of the emerald is oxide of chromium, while that of the beryl... Schorl is oxide of iron. In all the other characters they are nearly the same.

22. Species. Schorl, or Schorlous Beryl.

Schorl, Kirw. i. 286. Le Beril Schorliforme, Brochant, i. 224. Leucolite and Pyenite, Hauy, iii. 236.

Effem. Char.—Infusible. Original form of the crystals a regular hexahedral prism.

Exter. Char.—This mineral is usually found crystallized, in length masses, mixed with other substances, and generally imbedded in granite; the form of the crystals when they are regular, is a fixed-sided prism, which is sometimes truncated on its terminal edges, and sometimes the form disappears from its being deeply and longitudinally striated. The crystals are generally large.

Colour white, straw yellow, or reddish. Translucent or nearly opaque. External lustre shining between vitreous and resinous. Cross fracture imperfectly foliated, longitudinal, imperfectly conchoidal. Scratches quartz slightly. Brittle. Spec. grav. 3.514 to 3.530.

Chem. Char.—Infusible with the blow-pipe; with borax yields a transparent glass.

Constituent Parts.

| Kluproth. | Vauquelin. | Vauquelin, another analysis. | |----------|-----------|-----------------------------| | Silica, | 50 | 36.8 | | Alumina, | 50 | 52.6 | | Lime, | — | 3.3 | | Water, | — | 1.5 | | Fluoric acid, | — | 1 | | Lof, | — | 5.8 |

Localities, &c.—This mineral is generally found imbedded in granite; sometimes it is met with in gneiss, accompanied with lepidolite. It enters into the composition of a rock formed of quartz and gray mica at Altenberg in Saxony. A red variety of this mineral was formerly considered by mineralogists as a crystallized lepidolite. Schorlous beryl has been arranged as a subspecies of beryl; but its specific gravity, different degree of hardness, and especially its composition, are characters sufficiently distinct to constitute a separate species.

23. Species. Schorl.

This species is divided into two subspecies; 1. Black or common schorl, and 2. Tourmaline.

Subspecies 1. Black Schorl.

Schorl, Kirw. i. 265. Le Schorl Noir, Brochant, i. 226. Tourmaline, Hauy, iii. 31.

Effem. Char.—Electric by heat in the two opposite extremities; forms of the crystals derived from a rhomboid.

Exter. Char.—This mineral is found in masses, and disseminated, but most frequently crystallized. The primitive form of its crystals is an obtuse rhomboid; the integrant molecule is a tetrahedron. Its usual forms are, 1. A three-sided prism, with the lateral edges either truncated or bevelled; 2. The same prism having a three-sided obtuse summit, the sides corresponding to the lateral edges. The truncations, and bevelments of the lateral edges vary in the size of the faces, thus producing prisms of six and nine sides. The lateral faces of the three-sided prism are often convex. The lateral surfaces are longitudinally and deeply striated. The lustre, both external and internal, which is vitreous, varies between shining and weakly shining. The fracture is imperfectly conchoidal or uneven; cross fracture is sometimes convex on the one side and concave on the other. When black schorl is massive, it is found in separate pieces, thin, and apparently fibrous, parallel, or interwoven and divergent. The faces of these separate pieces are striated lengthwise. The fragments are indeterminate.

Colour velvet black of various shades. Commonly opaque, rarely translucent, except in small crystals. Streak gray. Inferior to quartz in hardness. Specific gravity 3.092 to 3.272.

Chem. Char.—Under the blow-pipe it froths up, and melts into a grayish white enamel.

Constituent Parts. Wiegleb.

| Alumina, | 40.83 | | Silica, | 33.33 | | Iron, | 20.41 | | Manganese, | 3.33 |

Physical Char.—Black schorl becomes electric by heat; and the electricity of one extremity of the crystal is positive, while that of the other is negative; but when it cools, it is said, that the nature of the electricity is reversed; the positive extremity becomes negative, and the negative becomes positive.

Localities, &c.—Black schorl is usually found in granite, gneiss, and other primitive rocks; in veins of tin and ores of iron; in the topaz rock of Schneeckenstein in Saxony, of which it constitutes a part. It is also met with in Switzerland, Spain, Hungary, and Britain.

Subspecies 2. Tourmaline.

Id. Kirw. i. 271. Le Schorl Electrique, Brochant, i. 229. Tourmaline Vert, Hauy, iii. 41.

Effem. Char.—The same as black schorl.

Exter. Char.—The tourmaline is found sometimes in masses and grains, but most commonly crystallized. The form of its crystals is a regular three-sided prism, with the edges, 1. Either truncated or bevelled. 2. A regular three-sided prism with the lateral faces convex, and terminating in an obtuse, three-sided prism, the sides of which correspond to the lateral faces at one extremity, and to the lateral edges at the other. 3. An obtuse, double three-sided pyramid, the faces of the one corresponding to the edges of the other. 4. A fixed-sided prism with equal angles. 5. A fixed-sided prism, the sides meeting two and two alternately under three obtuse angles. 6. A nine-sided prism, having three lateral angles acute, and fix obtuse alternately. 7. The same crystal having the three acute lateral edges truncated, and thus forming a twelve-sided prism. The surface of the crystals is sometimes smooth, but mostly... most frequently striated longitudinally. Lustre shining and vitreous. Longitudinal fracture conchoidal; cross fracture foliated. The direction of the plates is inclined to the axis of the prism. Fragments indeterminate; the crystals are usually opaque, when seen laterally.

The colour of the tourmaline is greenish, of various shades, yellowish brown, and very rarely indigo blue. The colours are usually very deep, and at first sight appear black. It is usually translucent, and sometimes approaching to transparent, particularly when it is seen in a direction perpendicular to the axis of the prism; but it appears opaque when it is seen in a direction perpendicular to the basis of the prism, even when the height of the prism is less than its thickness. It is harder than quartz. Brittle. Spec. gr. 3.056 to 3.363.

Chem. Char.—With the blow-pipe the tourmaline melts into a grayish white, porous enamel.

| Constituent Parts | |-------------------| | Bergman. | Vauquelin. | | Silica, | 37 | 42. | | Alumina, | 39 | 39. | | Lime, | 15 | 3.84. | | Oxide of iron, | 9 | 12.50. | | Manganese, | | 2. | | | 100 | 97.34. |

Bergman's analysis is of the tourmaline of Ceylon. Vauquelin's is that of the green tourmaline of Brazil.

Physic. Char.—The property of the tourmaline, of becoming electric by heat, has been already noticed as one of its distinctive characters. This physical property has occupied the attention of philosophers for a long time. It was observed by Lemery in 1719, and examined by Epinus in 1770. Pliny indeed mentions a reddish or purple-coloured stone, which being heated or rubbed, attracts light bodies. This is supposed to have been the tourmaline. This property is susceptible of various modifications. The electricity of the tourmaline may be conveniently exhibited by heating two crystals, suspending the one by a thread, and presenting successively to its extremities the extremities of the other crystal. The extremities which possess the same kind of electricity will be repelled, while those which possess a different kind will be attracted. If a crystal of tourmaline be broken while it is electrified, the fragments immediately present electrical poles, situated in the same direction as those of the entire crystal.

The extremity of the crystals of tourmaline which has the greatest number of faces, exhibits positive electricity, while the extremity having the smaller number of faces exhibits negative electricity. The proper degree of heat for exciting the electricity of tourmaline is from 100° to the boiling point of Fahrenheit. When heated beyond this point, it is deprived of its electricity, and recovers it only in cooling; but if the temperature be increased still more, the crystal becomes again electric, but the poles are reversed. The electric poles may be also reversed, by heating a crystal of tourmaline unequally, by means of a burning glass.

Loc. &c.—The tourmaline is found in almost all primitive mountains; the finest crystals are brought from Ceylon, Madagascar, Saxony, the Tyrol, Spain, and Brazil. The tourmaline of the Tyrol is found in a talcgy rock mixed with chlorite, mica, and hornblende. Those of Saxony and Spain are found imbedded in gneiss, but those of Brazil and Ceylon are in separate crystals. In Bohemia they are found in mines. The tourmaline is also a native of France, Sweden, Norway, and Britain.

24. Species. PISTAZITE.

Gloppy actynolite, Kirwan i. 168 Delphinite, Sauvage Voyages, No. 1918. Acanthicone, Arendalite, D'Andrade, Nich. Jour. 4to. v. 193. La Rappennante Vitreuse, Brochant, i. 510. Epidote, Hauy iii. 102.

Effem. Char.—Divisible parallel to the faces of a rhombohedral prism of 114°, and 65°.

Extern. Char.—Pistazite is found massive or crystallized in flattened four-sided prisms, terminated by four-sided pyramids, and also sometimes in regular six-sided prisms; the summit of the pyramid almost always truncated, as well as the lateral edges. The crystals are sometimes acicular and streaked longitudinally. Internal lustre shining. Fracture foliated or radiated. Fragments wedge-shaped and splintery.

Colour deep green, olive green, or greenish yellow. Translucent, sometimes transparent. Hard, easily scratches glass, and is brittle. Spec. gr. 3.45. Powder greenish yellow or whitish.

Chem. Char.—Fusible by the blow-pipe, and is converted into a brown slag, which blackens by continuing the heat.

| Constituent Parts | |-------------------| | Vauquelin. | Defortis. | | Silica, | 37 | 37. | | Alumina, | 21 | 27. | | Lime, | 15 | 14. | | Oxide of iron, | 24 | 17. | | Manganese, | 1.5 | 1.5. | | Lofs, | 1.5 | 3.5. | | | 100.0 | 100.0 |

Loc. &c.—Pistazite is found in Dauphiny, on the surface and in the fissures of an argillaceous rock, accompanied by quartz, amianthus, and feldspar, and in the Pyrenees in limestone; near Arendal in Norway; and in argillaceous schistus, north end of the island of Arran in Scotland.

25. Species. ZOYSITE.

This mineral, which was discovered by Baron de Zoys, and therefore bears his name, is considered by Hauy as a variety of Epidote.

It appears in prisms which are deeply furrowed or rhombohedral, and very much flattened. They are of a gray colour, or grayish yellow, with a pearly lustre.

Loc. &c.—Zoysite is found particularly in Carinthia, and also in the Tyrol and in the Valais*. Exter. Char.—Thumerstone is found in masses, differentiated and crystallized. The primitive form of its crystals is a right-angled prism, whose bases are oblique angled parallelograms, having their angles of $101^\circ 32'$, and $79^\circ 28'$. The integrant molecule is an oblique-triangular prism. The most common form of its crystals is a quadrangular prism, so oblique and flattened, that its angles become as sharp as the cutting part of a hatchet. The faces of the crystals are longitudinally striated, but the truncated faces are smooth. Externally lustre splendid; internal shining and vitreous. Fracture vitreous, sometimes rough and splintery. Fragments indeterminate, sharp edged. Massive thumerstone is composed of separate tectaceous, thin, and slightly curved concretions, with a smooth surface, which is somewhat irregularly striated.

The colour is clove brown, varying to violet blue, yellowish, and greenish gray. Massive thumerstone is only translucent. The crystals are semitransparent, and sometimes transparent. It is harder than feldspar, but less so than quartz; gives fire with steel, and diffuses an odour similar to what is produced by flint. Brittle. Spec. grav. 3.213 to 3.300.

Chem. Char.—Thumerstone froths up under the blow-pipe, and is converted into a grayish enamel, and with borax into a fine olive green enamel.

Constituent Parts.

| Constituent Parts | Klapproth. | Vauquelin. | |-------------------|-----------|------------| | Silica | 52.70 | 44 | | Alumina | 25.79 | 18 | | Lime | 9.39 | 19 | | Oxide of iron | 8.63 | 14 | | Manganese | 1. | 4 | | Lofs | 2.49 | 1 |

Localities, &c.—Thumerstone, which is hitherto a rare mineral, has been only found in veins and fissures of primitive rocks, and chiefly in rocks with a base of serpentine. It is usually accompanied with asbestos, rock crystal, and sometimes calcareous spar. It was first discovered at Thun in Saxony, from which it derives its name; but has been since found in the Pyrenees, in France, at Mount Atlas in Africa, in Norway, and in Cornwall in Britain.

27. Species. Quartz.

Effin. Char.—Divisible into a rhomboid, which is slightly obtuse.

Quartz, which is found, either massive, crystallized, or in rounded pieces, is one of the most abundant mineral substances. The primitive form of its crystals is a slightly obtuse rhomboid, of $94^\circ 4'$, and $85^\circ 56'$. The integrant molecule is a regular tetrahedron.

On account of the variety of forms and appearances, quartz has been divided into subspecies; into five by Werner; by others only into two, viz. rock-crystal and common quartz. We shall nearly follow the former subdivisions, which are, amethyst, rock-crystal, milk-quartz, common quartz, and pfae, including also ferruginous quartz.

Subspecies 1. Amethyst.

Id. Kirw. i. 264. L’Améthyste, Quartz-hyalin Violet, Hauy, ii. 417.

Exter. Char.—The amethyst is found frequently crystallized, but it is also found massive and in rounded pieces. 1. The form of its crystals is a regular six-sided prism, terminated by a six-sided pyramid, the sides of which correspond to those of the prism. 2. A double six-sided pyramid. Fracture conchoidal, rarely splintery or fibrous. Fragments indeterminate, sometimes wedge-shaped. Massive amethyst is composed of separate pieces, which are sometimes granulated, sometimes scoriiform when the crystals are combined together.

The colour is commonly violet blue of various shades, blackish brown and greenish white. External lustre resplendent; internal resplendent and shining vitreous. It varies between transparent and translucent. Scratches glass. Brittle. Spec. grav. 2.653 to 2.750.

Chem. Char.—Entirely infusible under the action of the blow-pipe.

Constituent Parts. Rofe.

| Constituent Parts | Silica, | Alumina, | Oxide of iron and manganese, | |-------------------|---------|----------|-----------------------------| | | 97.50 | .25 | .50 | | | | | | | | 98.25 | | |

Localities, &c.—Amethyst is found in Bohemia, Saxony, Siberia, very abundant in the Uralian mountains, Hungary, and Auvergne in France. It is usually met with in the veins of metalliferous mountains, very rarely in granitic mountains. It is frequently met with crystallized, lining the cavities of balls of agate; in amygdaloid and porphyry rocks.

Uses.—When the amethyst is cut and polished, it assumes an agreeable colour and lustre, so that it is employed in jewellery.

Werner has divided the amethyst into two varieties, the common and fibrous; the latter being chiefly characterized by its fibrous fracture and resinous lustre. This latter variety too, is only found massive.

Subspecies 2. Rock Crystal.

Mountain Crystal, Kirw. i. 241. Le Cristal de roche, Brochant, i. 243. Quartz-hyalin Limpid, Hauy, ii. 417.

Exter. Char.—Rock crystal is usually found crystallized, sometimes in rounded pieces, but rarely massive. The form of its crystals is, 1. A six-sided prism, having one of its bases or both surmounted by a sharp pointed pyramid; the sides of the pyramid and prism corresponding. This is its most usual form; but it exhibits many apparent varieties, arising from modifications in the magnitude of one or several of the faces at the expense of the others. 2. A double six-sided pyramid, which is sometimes perfect, and sometimes truncated on the edges of the common base; and sometimes too, three alternating faces on each pyramid are larger than the others, giving to the crystal the appearance of a cube. 3. A simple, very acute pyramid with six sides, having its summit, and often also its base, acuminated with six faces; but this is rather an irregularity in the crystallization than a new form.

The crystals of this mineral are sometimes very large, and they are also found very small. In the rounded pieces the external surface is rough, but in the perfect crystals crystals the faces of the prism are striated transversely; but those of the pyramids and acuminations are smooth. The lustre is refulgent and vitreous; fracture perfectly conchoidal, sometimes, however, foliated; fragments indeterminate, very sharp edged.

Colours of rock-crystals are greyish white, yellowish white, pearl grey, yellowish and blackish brown. Internally it is sometimes iridescent. It is transparent, sometimes semitransparent. By looking across one of the faces of the pyramid, and the opposite face of the prism, double refraction is produced. Scratches glass, and gives sparks with steel. Somewhat fragilable; Spec. grav. 2.650 to 2.888.

Chem. Char.—Entirely infusible before the blow-pipe.

| Constituent Parts | Bergman | |------------------|---------| | Silica | 93 | | Alumina | 6 | | Lime | 1 |

Physical Char.—It is sometimes phosphorescent; two crystals, by being rubbed together, exhibit a little light in the dark, and give out a peculiar odour, which is somewhat empyreumatic.

Localities &c.—Rock-crystal is most commonly found in veins of primitive rocks, and particularly in granite; in dikes lining the cavities of these rocks. The finest crystals are now brought from Madagascar, but it is a very frequent mineral in most countries, as in the mountains of Switzerland, where it was formerly dug out of the faces of lofty precipices by the inhabitants. It is also found in Bohemia, Saxony, Hungary, and in Cornwall in England, and different parts of Scotland, as in the island of Arran, in the cavities of the granite mountains, and in Cairngorm in Aberdeenshire, the latter, which are well known by the name of Arran stones and Cairngorms, are usually of a smoky colour, owing, it is supposed, to iron or manganese; probably to the latter, for from some experiments which we have made, the colour entirely disappears by exposing the crystal to a strong heat, and from other observations it appears that the colouring matter is also destroyed by the action of light.

Rock crystal sometimes contains schorl, amianthus, actinolite, mica, and titanium. Crystals are also sometimes met with in cavities containing a drop of water, and a small quantity of air.

Uses.—Rock crystal, on account of its lustre and transparency, is employed in jewellery, and particularly when it is coloured, as those from Cairngorm in the north of Scotland, many of which are held in high estimation.

Subspecies 3. Rosy Red or Milky Quartz.

Rosy Red Quartz, Kirw. i. 245. Quartz laitieux, Brongniart, i. 246. Quartz hyalin laitieux, Hauy, ii. 420.

Exter. Char.—This mineral is always found massive. It is indeed said by Emmerling, that it has been found crystallized, in small six-sided prisms, terminated by a six-sided pyramid, at Rabenstein in Bavaria. Internally, its lustre is shining, rarely refulgent; resinous; fracture perfectly conchoidal, and fragments indeterminate. It varies between semitransparent and translucent.

The colour is sometimes milk white; but its principal colour, it is said, is pale rose red. In its other characters it agrees with rock crystal.

It is suspected that this mineral is composed of silica and oxide of manganese, to the latter of which the colour is owing.

Localities &c.—Milky quartz forms beds in primitive mountains; at Rabenstein in Bavaria it is met with in a large grained granite. It is also found in Finland, Greenland, Saxony, Siberia, and the western part of Invernessshire in Scotland.

Uses.—The semitransparency, the fine colour, and the polish of which it is susceptible, have introduced this mineral to be employed in jewellery.

Subspecies 4. Common Quartz.

Quartz, Kirw. i. 242. Le Quartz commune, Brongniart, i. 248. Quartz hyalin amorphe, Hauy, ii. 425.

Exter. Char.—Common quartz is found in various forms, massive, disseminated, in grains, and rounded pieces. It is sometimes stalactitical, globular, kidney-form, tuberculated, cellular, perforated, and corroded; sometimes also it is crystallized, and the crystals are either true, or supposititious. The true crystals are grouped together in reniform, rounded, or radiated masses; the form is the same as that of rock crystal. The pseudo crystals derive their figure from the substances on which they are formed, as the cube from fluor spar, the octahedron from the same, the six sided table from barytes, the acute six-sided pyramid from calcareous spar. The surface of the true crystals is similar to that of rock crystal, but that of the pseudo crystals is rough, and the lustre is dull. Fracture of common quartz is small, conchoidal; sometimes large, splintery, and sometimes imperfectly foliated, or fibrous, with large parallel fibres. Fragments indeterminate, with sharp edges, very rarely rhomboidal. It is commonly translucent, rarely semitransparent. The colour is milk white, snow white, reddish white, and blood and flesh red, with many shades of these colours. Scratches glass.

Spec. grav. 2.640 to 2.654.

Chem. Char.—Infusible before the blow-pipe. Silica forms the principal constituent part; but among the numerous varieties of common quartz, there are no doubt slight differences in the nature and quantity of the materials which enter into its composition. The different shades of colour are owing to different portions and different states of metallic substances.

Localities &c.—Common quartz is one of the substances of most frequent occurrence in all kinds of rocks, forming one of the chief component parts of primitive mountains; sometimes in entire beds, or whole mountains, as in the islands of Ilha and Jura in Scotland. It is also frequent in veins, very common in stratiform rocks, where it constitutes the base of sandstone: in alluvial rocks it is met with in rounded pieces, or in the form of sand.

Uses.—Common quartz is employed in the manufacture of glass instead of sand; in the fabrication of flint, and as a flux for calcareous ores of iron.

A variety of this, called aventurine, is sometimes held in considerable estimation. It is the quartz hyalin aventurine. Siliceous aventurine of Hauy, and the natural aventurine of De Lisle. It is of a deep red, gray, green, or blackish colour, marked with spots sometimes of a yellowish, and sometimes of a silvery appearance, which proceed from very thin pieces of pure quartz disseminated in the mafs. It ought not to be confounded with quartz mixed with mica, or micaceous quartz, which is a compound rock. On the contrary, the diversity of colours seems to be owing to numerous fissures which are arranged nearly in the same direction.

Aventurine is found near Valles, in the department of Deux Sevres in France, in the form of rounded stones, which are reddish; at Cape de Gates in Spain, of a whitish colour, with silvery spots; in Arragon, which affords several varieties; near Madrid, among rounded fragments of granite; at Facebay in Transylvania, where it is of a black colour, with very small golden spots; and in the neighbourhood of Catharineburg in Siberia.

The name aventurine is derived from the following circumstance. A workman having dropped by chance, par aventure, some brass filings into a vitreous matter in the state of fusion, gave the mixture this name, of which was afterwards made vases and other ornamental objects. Mineralogists gave the same name to natural substances which have a striking resemblance to this artificial production. Hauy, ii. 422.

Subspecies 5. Prase.

Prasium, Kirw. i. 249. La Prase, Brochant, i. 252. Quartz Hyalin Vert obscure, ii. 419. Quartz Prase, Brongniart, i. 280.

Exter. Char.—This mineral possesses all the characters of quartz in general. It is most commonly found massive, and very rarely crystallized. The crystals, which are usually small, have the form of rock crystal.

The colour is usually light green; the external surface is rough and glittering; the internal shining and vitreous; it is translucent; the fracture imperfectly conchoidal, and sometimes coarse splintery; fragments sharp-edged. When it is massive, it is composed of distinct concretions, which are granulated prismatic, or cuneiform, the surface of which is rough and transversely striated.

Localities, &c.—Prase is found at Brietenbrunn near Schwartzenberg in Saxony, in a metallic vein, accompanied with magnetic pyrites, galena, blende, calcareous spar, and actinolite. It is also found in Bohemia, in Finland, near lake Omega, and in Siberia.

Use.—As it is susceptible of a fine polish, prase is employed in jewellery.

This mineral ought not to be confounded with quartz coloured by means of chlorite, which latter is of a brighter green, but opaque.

Subspecies 6. Ferruginous Quartz, or Iron Flint.

Le Guillou Ferrugineux, Brochant, i. 248. Quartz Rubigineux, Brongniart, i. 281. Quartz Hyalin hématoïde, Hauy, ii. 420. Eifelkiefel of the Germans.

Exter. Char.—The peculiar character of this mineral seems to be owing to a large proportion of oxide of iron, which renders it opaque. It is usually found massive, but it sometimes also assumes a crystalline form, which is a prism with six equal sides, acuminated at each extremity with three planes. The colour is of a yellowish brown, sometimes of a brownish red, and of a bright blood red. It is usually opaque, or only transparent at the edges. External lustre refulgent; internal shining and vitreous. Fracture imperfectly conchoidal; fragments angular, but not very sharp-edged. Concretions small grained and distinct. It is harder than common jasper. Not very brittle.

Localities.—This mineral is found in veins of ironstone in Saxony, and in England, where it is accompanied with sulphate of barytes.

Ferruginous quartz is distinguished from jasper, to the red variety of which it has a striking resemblance, by its shining fracture, which is also vitreous and conchoidal; its property of crystallizing; and according to Brongniart, by having no alumina in its composition, which he properly considers as an essential characteristic.

28. Species. Hornstone.

Hornstone, Kirw. i. 303. La Pierre de Corne, Brochant, i. 254. Petrofilex, Hauy, iv. 385.

This mineral is met with in masses and also in rounded balls. The colour is usually gray; it is translucent at the edges, the fracture splintery or conchoidal; it has little lustre; is so hard as to scratch glass, and give fire with steel; and its spec. grav. is from 2.699 to 2.708.

The diversity of fracture which has been observed in hornstone, has led to the subdivision of this species into three subspecies, viz. splintery hornstone, conchoidal hornstone, and woodstone.

Subspecies 1. Splintery Hornstone.

Hornstone Ecailleux, Brochant, i. 255. Petrofilex Squamosus, Wallerius, i. 280.

Exter. Char.—This mineral is found massive, or in rounded pieces. It has scarcely any lustre; the fracture is fine, splintery; fragments sharp-edged; translucent at the edges. It is scarcely so hard as quartz; it is brittle.

The colour is bluish gray, smoke and pearl gray, sometimes greenish and yellowish gray, more rarely olive and mountain green. Sometimes there is a mixture of these colours, arranged in spots and stripes. Spec. grav. 2.654. Kirw.

Chem. Char.—According to some mineralogists, this variety of hornstone is fusible before the blow-pipe, but according to others it is infusible without the addition of borax.

The following are the constituent parts of a hornstone analyzed by Kirwan.

| Silica | 72 | |--------|----| | Alumina | 22 | | Carbonate of Lime | 6 |

100

Localities, &c.—This variety of hornstone is chiefly found in veins in primitive mountains. It is also found in rounded pieces in alluvial rocks, and it constitutes the chief basis of hornstone porphyry, as at Dannemora and Garpenberg in Sweden. It is met with in veins at Freyberg, Schneeberg, Johann-Georgenstadt, and Gerdorf in Saxony.

Subspecies Subspecies 2. Conchoideal Hornstone.

Petroflex Equabilis, Wallerius, i. 281. Le Hornstein Conchoide, Brochant, i. 258.

Exter. Char.—This mineral is always found massive, and seems to approach in its characters very nearly to the preceding variety or subspecies, excepting in the fracture, which is perfectly conchoideal.

Localities, &c.—This subspecies is found in beds and veins, when it is sometimes accompanied with agate. It has been found accompanying gneiss at Goldberg in Saxony, and fine specimens of both subspecies are met with in the island of Rona near Sky in Scotland, where it seems to form a considerable vein, traversing a gneiss rock.

Subspecies 3. Woodstone, or Petrified Wood.

Woodstone, Kirw. i. 215. Le Holzstein, Brochant, i. 259. Quartz Agathe Hyloide, Hauy, ii. 439.

This subspecies possesses more distinctive characters than the former; and as it seems to be wood, retaining its original texture, converted into hornstone by some petrifying process, it is usually found in insulated masses, or in rounded pieces. It has the external appearance of wood, for the surface is rough and uneven, or longitudinally striated; internally it is glimmering, but sometimes dull, having a vitreous lustre. The fracture most frequently exhibits the fibrous texture of the wood. The cross fracture is sometimes splintery or imperfectly conchoideal. The fragments are indeterminate, and slightly sharp-edged. The most common colour is dark gray, ash gray, grayish white, and sometimes cochineal and blood red. Different colours appear in the same mineral, forming spots, clouds, or stripes. It is commonly translucent at the edges, sometimes entirely transparent, and sometimes opaque. It is hard and brittle.

Localities.—Woodstone is met with in Bohemia, Saxony, and Siberia, and on the banks of Loch Neagh in the north of Ireland, particularly, as we have been informed, near places where some of the rivers discharge their waters into the lake.

Uses.—This mineral is generally susceptible of a fine polish, and is therefore employed in jewellery.

29. Species. Flinty Slate, or Siliceous Schistus.

This species is divided into two subspecies or varieties, viz. common siliceous schistus, and Lydian stone.

Subspecies 1. Common Siliceous Schistus.

Siliceous schistus, Kirw. i. 306. Schiste silicieux commun, Brochant, i. 283.

Exter. Char.—This mineral is found in masses or rounded pieces, and it is frequently traversed by veins of quartz of a grayish white, or coloured red by means of iron. This, it is said, is a distinguishing characteristic of siliceous schistus which it rarely wants (Brochant). Internally it is dull, very rarely a little glimmering. The fracture in the small is compact, sometimes splintery, and sometimes imperfectly conchoideal; but in the great or large masses it is flaty, a character which almost always disappears in the small fragments. The fragments are sharp edged. The colour is blackish, greenish, or smoke gray. It is commonly opaque, rarely translucent at the edges. It is hard and brittle.

Chem. Char.—Before the blow-pipe, gray siliceous schistus becomes white and friable; the black assumes a darker colour, and is a little vitrified at the edges.

Constituent Parts. Wiegbe.

| Silica | 75 | |--------|----| | Magnesia | 4.5 | | Lime | 10 | | Iron | 3.54 | | Inflammable matters | 5.02 | | Lofe | 1.86 |

100.00

Localities, &c.—Siliceous schistus is met with in Bohemia, Saxony, Switzerland, and Siberia; at Leadhills in Scotland, and also at Carlops, near the termination of the great coal field to the south of Edinburgh.

The geological position of this stone is not precisely determined. In Scotland it is connected with those rocks which come under the denomination of transition rocks; but according to different descriptions it seems to have been confounded with argillaceous schistus, with which indeed it possesses some common properties; and some mineralogists regard it as an argillaceous schistus, having a larger proportion of siliceous earth. In support of this opinion, siliceous schistus has been found in situations where it is subordinate to argillaceous schistus.

Subspecies 2. Lydian Stone.

Bafunite, Kirw. i. 307. La Pierre de Lydie, Brochant, i. 286. Roche Corneenne, Hauy, iv. 434.

This stone, which is of a grayish, bluish, or velvet black, is found in masses, and in rounded pieces of a trapezoidal form, which are also traversed with veins of whitish quartz. The external surface is smooth and weakly shining; the internal is glimmering. The fracture is even, sometimes slightly conchoideal or uneven, rarely splintery; in large masses it is flaty. The fragments are sharp-edged, and sometimes assume a cubical form. It is commonly opaque, and rarely translucent at the edges. It is scratched by quartz; brittle. Spec. grav. 2.415 to 2.880.

Localities.—Lydian stone is found in similar places with the former variety.

Uses.—This stone has been long known under the name of touchstone, because it is employed to ascertain the purity of gold. From this use it obtained the name of bursier or the trier, and it was called Lydian stone, because it was found in Lydia. When it is employed as a touchstone, the gold to be tried is rubbed on its polished surface; on the metallic trace which remains nitric acid is poured, and the quantity of alloy is judged by the degree of change which takes place, this being compared with traces made and treated in the same way with needles differently alloyed and prepared for the purpose. This test, it is to be observed, is not perfectly accurate, but is sufficiently so for those who are much employed in the use of it. The property which renders this mineral fit for the above purpose depends on its degree of hardness, while it presents at the same time a smooth and even fracture without being perfectly smooth. Other stones possessing similar properties, ties, such as several varieties of basalt, are conveniently employed for the same purpose.

30. Species. Flint.

Flint, Kirw. i. 301. Pierre à fusil, Brochant, i. 263. Quartz-Agathe Pyromaque, Hauy, ii. 427.

Exter. Char.—Flint is found massive, disseminated, in angular fragments, in globular masses, tuberculated, and perforated. The surface is sometimes rough, sometimes uneven, and sometimes smooth. The white crust which it is often covered, is considered by some mineralogists as an incipient decomposition. The external lustre is dull or a little glimmering; the internal is weakly shining; the fracture is perfectly conchoidal, the fragments sharp edged. The colour is usually gray, smoke gray, sometimes perfectly black. Various colours appear in the same mineral, presenting spots, stripes, and clouds. Commonly translucent at the edges; scratches quartz: spec. grav. 2.58 to 2.99.

Chem. Char.—Entirely infusible before the blowpipe.

| Constituent Parts | Klaproth | Vauquelin | |------------------|----------|-----------| | Silica | 98 | 97 | | Lime | .50 | | | Alumina | .25 | | | Oxide of iron | .25 | | | | 99.00 | 98 |

Physical Char.—Two pieces of flint rubbed together in the dark, give out, like quartz, a phosphoric light.

Localities, &c.—Flint is never found in primitive mountains, excepting in very small quantity, and very rarely, in some veins; in alluvial rocks it is sometimes met with in rounded pieces; but it is most abundant in stratified mountains, particularly in beds of limestone, marl and chalk, in which it is disposed in parallel layers. It is met with in Saxony, Denmark, Sweden, Poland, and Spain, and is very abundant in chalk beds in the north of France, and also in different parts of England. It is also met with distributed in layers in the white limestone rocks, on the north coast of Ireland. In the department of Jura in France, globular masses of flint have been found with cavities containing sulphur.

The singular geological relations of this mineral have greatly puzzled naturalists, who are fond of such speculations, and are never satisfied till they have accounted for every thing; however scanty and defective the data may be on which their hypotheses are formed. It is on this account that the theories which have been proposed, to explain the formation of flint, offer nothing more than the illusive and most groundless conjectures; and indeed the same remark is equally applicable to theories of the earth in general. It has been already observed that flint is regularly disposed in layers, in the beds of chalk or limestone in which it is found. In an insulated mass of white limestone near Port Ruth on the north coast of Ireland, which we had an opportunity of examining, the balls of flint were disposed in this way with great regularity. When the bed of limestone is of no great thickness, it contains only one layer of flints, but in thicker beds there are two layers of flints, the one near the top, and the other near the bottom of the bed. These layers of flint, too, it is to be observed, have exactly the same inclination as the strata of limestone. According to one set of theorists, the flint being in a state of fusion, was ejected from the bowels of the earth, and deposited in the places where it is now found. This opinion carries along with it its own absurdity; for admitting that the flinty matter has been in a state of fusion, it is impossible to suppose that it could be deposited with so much uniformity and regularity, by being projected according to the conjecture of the philosophers who maintain this opinion. Had this been the mode of its formation, masses of flint would have been found throughout every part of the chalk or limestone beds, and not in regular layers, as is really the case.

According to another opinion, by which the formation of flint is supposed to be accounted for, cavities were produced, while the chalk and limestone were yet in a soft state, in consequence of the air extricated during the evaporation of the water; and the flinty matter in solution was introduced into these cavities by infiltration from above. But the same argument is equally forcible against this opinion. It is impossible to conceive that the cavities could be so regularly and uniformly produced by the extrication of the air. They would have been found through every part of the beds of chalk and limestone where flint is met with. And besides, even allowing that this flinty matter was held in solution by water, it might naturally be asked, why the greatest proportion of it was not deposited near the surface, when it first came in contact with the chalk or limestone, rather than to have continued to pass through the different beds, and form masses of solid flints at the greatest depths, in as great quantity as near the surface.

A third opinion, which some imagine to be less improbable than either of the former, supposes that flints have been entirely produced by marine animals deposited during the formation of the strata in which they are contained. This opinion seems to derive some support from the remains of marine animals, which are not unfrequently found included in nodules of flint. It is no rare occurrence to meet with shells thus attached to these nodules, and converted into flinty matter, but at the same time retaining their original form and appearance in the most perfect manner.

Uses.—The extensive use of this mineral, in consequence of its property of striking fire with steel, as gun flints, is well known. Flints are employed also as a substitute for quartz in the manufacture of glass and porcelain, and in the fabrication of smalt. The coarser kinds, or such as are perforated and carious, are applied to the purposes of building and millstones. Sometimes the colours and the polish of flint are so fine as to have brought it into use in jewellery.

As flints are found in greatest abundance in France and England, the principal manufactures of gun flints are carried on in these countries. A particular account of this manufacture in France has been given by Dolomieu and Salivet, "Journal des Mines," No. 33, pp. 693 and 713. The whole process, which according to the description of Dolomieu is divided into four stages, is very simple.

1. After having fixed upon a mass of stone fit for for the purpose, the first part of the operation is to break the stone into pieces of convenient size. With this view the workman, seated on the ground, places the stone on his left thigh, and strikes it with small strokes, to divide it into pieces of a pound or a pound and a half weight, having large surfaces and smooth fractures, and at the same time he avoids splitting or shaking the stone by too feeble or too violent strokes.

2. In the next part of the operation the nicest management and dexterity of hand are required; for by repeated strokes splinters of the proper size to form gun flints are detached; one is separated at every stroke. During this operation he holds the mass of stone in his left hand. The splinters are about 1 inch broad, 2 long, and two lines thick in the middle. They are slightly convex above, and concave below; thick at one edge, and thin at the opposite edge.

3. The flint is brought to a regular shape during this part of the operation; and,

4. The edge of the gun flint which strikes fire, is brought to a straight line by placing it on a sharp iron instrument, and giving it five or six small strokes with a circular hammer (roulette). This finishes the operation, and the whole time of making a flint is not equal to a minute. With masses of stone that work easily, an expert workman will prepare 1000 good splinters in a day. It requires another day to bring to the proper shape 500; so that in three days he can split off from the mass and completely finish 1000 gun flints.

31. Species. CALCEDONY.

This species has been divided into two subspecies or varieties; common calcedony and carnelian.

Subspecies 1. Common CALCEDONY.

Id. Kirw. i. 298. La Calcedoine Commune, Brochant, i. 268. Quartz Agathe Calcedoine, Hauy, ii. 425.

Exter. Char.—This mineral is found massive, in rounded pieces, which are globular, reniform, botryoidal, flabelliform, cellular; and sometimes also it is crystallized in the form of a cube, rhomboid, a simple pyramid with three and six faces; but these are supposed to be pseudo crystals, or merely a crust of calcedony on the crystals of other substances. The external surface is most commonly uneven, sometimes rough, and rarely smooth. External lustre is accidental; internal glimmering, rarely a little shining; fracture even, sometimes imperfectly conchoidal or splintery; fragments sharp-edged.

Colour white, grayish or bluish white, yellowish or blackish; various colours appear in spots, clouds, stripes, and veins. Sometimes when it is cut it is iridescent; commonly translucent, rarely semitransparent. Harder than flint. Brittle. Spec. grav. 2.600 to 2.700.

Chem. Char.—Before the blow-pipe it is infusible.

Constituent Parts.

| Bergman. | |----------| | Silica, | 84 | | Alumina, | 16 | | A trace of iron, | — |

Localities, &c.—Calcedony is most usually met with in globular masses in amygdaloid, as at Oberstein, in the duchy of Dux Ponts. It is found also in Saxony, Silesia, and Siberia, in Iceland and the Faro islands; in the north of Ireland; and in several of the western islands of Scotland. The cavities of the balls of calcedony are often lined with crystals of quartz and amethyst.

Uses.—Calcedony takes a fine polish, and is therefore employed in jewellery.

2. Subspecies. CARNELIAN.

Id. Kirw. i. 300. La Cornaline, Brochant, i. 272. Quartz-Agathe Cornaline, Hauy, ii. 425.

This mineral is found in masses, or disseminated, but most frequently in rounded pieces of a globular, kidney form, or stalactitical shape. External surface rough and uneven; internal lustre glimmering, or slightly shining; fracture perfectly conchoidal; fragments very sharp-edged; most common colour blood red of various shades, and sometimes reddish brown or wax and honey yellow; semitransparent, hard, and brittle. Spec. grav. 2.59 to 2.73.

Chem. Char.—Carnelian is infusible before the blowpipe, but loses its colour, and becomes white.

Localities, &c.—Carnelian is found in similar circumstances, and in similar places with common calcedony, but is of less frequent occurrence. The finest carnelians are brought from the east, and thence they are denominated oriental.

Uses.—The carnelian is employed for the same purposes as common calcedony.

Observations on Agate.—As common calcedony and carnelian, along with jasper, constitute the base of the greater number of agates, it may be here proper to introduce a few remarks on the mineral substances which are included under this name, and on the theories of their formation.

The term agate is of very general application, comprehending numerous varieties, which are chiefly distinguished by the arrangement and disposition of the colours with which they are marked, and from which they have derived particular names. The following are some of the principal varieties of agate. 1. Fortification agate, in which the different coloured stripes are arranged in a zigzag manner, presenting something of the appearance of a fortified town. 2. Landscape agate, in which the colours and shades are so arranged as to exhibit the appearance of a landscape. 3. Band or ribbon agate, in which the various colours are disposed in stripes or zones, which are usually in straight lines, but sometimes concentric. To this variety of agate, when the zones or stripes are arranged parallel to each other, and distinctly marked, the name of onyx was given by the ancients. The name onyx, which signifies the nail of the finger, is derived from the whitish colour resembling that part of the body. They also gave the name of sardonyx to a variety of the same stone, of a flesh colour, and afterwards the compound name sardonyx was given to another variety, in which a whitish layer of the onyx, having some degree of transparency, covered another layer of a flesh red, the colour of which latter appeared through the former in the same manner as the colour of the flesh appears through the nail. But in in the end, the name of onyx seems to have been applied to all stones formed of layers of different colours.

4. Moss agate. In some varieties of agate filaments of a greenish or other colour, having the appearance of some species of conveves or mucil, are observed, and these have been denominated moss agates. Some have supposed that these filaments have been real mosses or conveves, enveloped by the filaceous matter. In some also delineations of a brown or black colour, exhibit the appearance of trees or shrubs. This dendritical appearance is ascribed by some to the infiltration of iron or manganese into the natural fissures of the stone. The finest agates of this variety, it is said, are brought from Arabia, by the way of Mocha, on the coast of the Red Sea; and hence they are known by the name of Mocha stones. Besides these varieties, there are several others, as tubular agate, when it is composed of calcined, which seems to have been in the form of stalactites, and afterwards filled up with a different mineral substance, or at least of a different colour; clouded agate, presenting the appearance of clouds; radiated or bellied, when the different colours are arranged in rays; breccia agate, composed of fragments of different kinds of agate, and cemented together by filaceous matter, and constituting a real breccia; spotted agate, when the colours are disposed in points or spots; petrified agate, which seems to have been wood penetrated with the matter of agate; coral agate, having the appearance of coraloid; jasper agate, in which the predominant part of its composition is jasper.

The formation of agate has been the subject of much controversy among contending theorists; for while one party conceives that it affords the strongest proofs of being produced by means of heat, or from a state of fusion, another party seems to be equally convinced that it supplies them with the most certain evidence of having been formed from an aqueous solution.

Besides other strong objections that might be urged against the opinion of agate being formed from a state of fusion, the uniformity and regularity in the arrangement of the different kinds of matter of which it is composed, seem quite hostile to it, and, excepting to those who are previously prepossessed with such an opinion, will, we presume, appear altogether insurmountable; for it is inconceivable, that in a mass of melted matter, whether it have been in a state of fusion in the place where it is now found, or projected from the bowels of the earth into the strata which are now its repository, while in a soft state, could arrange itself into layers, some of them often extremely thin, and disposed in stripes, concentric circles, spots, while these various kinds of matter exhibit very slight shades of difference in their constituent parts. It cannot even be imagined that all this could have been effected, even by the slowest and most gradual process of cooling.

In accounting for the formation of agate by solution in water, it is said that the cavities in the rocks which contain agate, were formed in consequence of the evolution and extrication of air, while those rocks were in a state of softness; and that the matter of which agate is composed, was introduced in the state of an aqueous solution by means of infiltration. But objections, equally insurmountable, might easily be adduced against this theory; and one of the first that presents itself is derived from the diversity of matter deposited in masses of agate. This objection, indeed, is attempted to be obviated by supposing that the agate composed of different kinds of matter was derived from different kinds of effective solutions; but this is only removing the difficulty a step farther; for, can it easily be conceived, that a very thin layer of one kind of matter being deposited, and this, let it be supposed, of a white colour, the solution was changed, from which proceeded another thin layer; that the solution was again changed, and deposited a third kind of matter; and after another change, a fourth kind, or perhaps that the deposition of the first kind of matter again commenced. But if infiltration from an aqueous solution have really been the mode of formation of this mineral, how comes it, it may be fairly asked, that the depositions from the different kinds of solution have not been arranged, at least in the larger cavities, in strata or zones parallel to the horizon; because it seems natural to suppose that the deposition of stony matter, from a state of solution in water, would be influenced by gravitation, and thus be horizontally arranged? We are aware, indeed, of an objection which may be made to this observation. It will be said that the influence of gravity has in this case been counteracted by the action of affinity between the stony matter in solution, and the sides of the cavity in which the agate is formed; but whatever effect this might have in the smaller cavities, its influence would be diminished in those of larger capacity.

To what we have now said on this subject, which, it must be acknowledged, is more curious than useful, we shall only add a circumstance which, so far as we know, has not been noticed by geologists; but it seems to be of considerable importance in the establishment or subversion of the theory of the formation of agate by means of infiltration in the state of aqueous solution. It will be allowed, we presume, that all agates found in the same horizontal position, or at the same depth from the surface, from which the aqueous solution is understood to have proceeded, were formed from the same solutions; at least those agates which are contiguous to each other, that is, within the space of a few yards, or even of a single yard. Now, if this be admitted, all the agates which have derived their materials from the same solutions, ought to be exactly of the same kind, because their origin is contemporaneous, and it is derived from the same solutions. To ascertain this point with precision, it will be necessary to examine agates in their native repositories; and although we shall not pretend confidently to decide the question, because our observations with this view have not been sufficiently varied and extensive, yet we strongly suspect, that it will appear, from future investigations, that agates, and even such as are almost contiguous to each other, have been formed of very different materials, or of similar materials arranged in a very different manner. To those who are fond of such speculations we recommend this as a subject of investigation.

Localities.—Agates are found in great abundance in different parts of the world. They are sometimes distributed indiscriminately with the rocks which contain them, sometimes in beds or layers, in interrupted masses, and sometimes in thin beds, where there is scarcely any interruption of continuity. This last mode of arrangement, however, is rare. Agates are sometimes found in metallic veins, or are mixed with metallic substances, as the sulphures of lead and silver. It would appear, too, that agates also exist in primitive rocks. Saufure has observed them in granite, containing nodules of the same granite, and penetrated with iron pyrites. He has observed also at the same place, near Vienne, in the department of Isere, thin layers of calcedony alternating with gneiss; but porphyries and similar rocks are the usual repositories of agate. These stones are found in great variety and abundance at Oberstein, in the department of Mont-Tonnerre, in France, in a rock of amygdaloid of a peculiar nature, and full of cavities of all sizes. This rock is considered by Dolomieu as a volcanic tufa; but according to other mineralogists, and particularly Faujas de St Fond, who has given a minute description of it *, it is considered as a porphyry or amygdaloid, with a basis of trap, which is very subject to decomposition. The globular masses of agate are disposed in this rock without any order, and are usually enveloped with a peculiar greenish earth, but which contains no copper. In the geodes of agate found at Oberstein, jasper, amethyst, carbonate of lime in crystals, chabacite, a species of zeolite, and some portion of titanium, have been observed; but not the least trace of any organized body. Digging, polishing, and forming into a great variety of ornamental objects, constitute the chief employment of the inhabitants of Oberstein.

Agates are found in abundance in different parts of Scotland: but the largest and finest are met with in the neighbourhood of Montrose and Stonehaven; in the rocks near Dunbar on the east coast, and in the rocks about Dumure, on the shore of Carrick in Ayrshire.

32. Species. HYALITE.

Id., Kirw. i. 296. Muller's glafs of the Germans. Lavva glafs of many.

Exter. Char.—This substance is found in grains or masses, or in thin layers on other minerals. It has much the appearance of gum, and is usually cracked. The lustre is shining and vitreous; fracture conchoidal, sometimes foliated; fragments sharp-edged.

Colour grayish white or yellowish; and, according to Kirwan, pure white. Translucent, sometimes semi-transparent; has considerable hardness, and is brittle. Spec. grav. 2.110.

Chem. Char.—Infusible at 150° Wedgwood, but melts with soda.

Constituent Parts.

| Silica | 90 | |--------|----| | Water | 10 |

Localties, &c.—Hyalite is found in rocks of amygdaloid, or wacken, near Franckfort on the Maine.

33. Species. OPAL.

This species is divided into four subspecies or varieties.

Subspecies 1. PRECIOUS OPAL.

Opal, Kirw. i. 289. L'Opale Noble, Brochant, i. 341. Quartz-reinite Opalin, Hauy, ii. 434.

Exter. Char.—This mineral is found massive or disseminated, and sometimes in veins; internal lustre splendid and vitreous; fracture perfectly conchoidal; fragments sharp-edged.

Colour milk-white, clear or pale, and sometimes bluish gray; and by holding it in different lights, a very bright and varied play of colours, the principal of which are golden yellow, scarlet red, bright blue, green and gray, is seen. It is commonly translucent, rarely semitransparent; pretty hard and brittle. Spec. grav. 2.114.

Chem. Char.—The precious opal treated with the blow-pipe splits and cracks, and loses its transparency, but is not melted.

Constituent Parts. Klaproth.

| Silica | 90 | |--------|----| | Water | 10 |

Localties.—The finest opals are found at Czerwenitz, not far from Czschau in Upper Hungary, in an argillaceous decomposed porphyry, which according to some mineralogists is a gray flone (graustein of the Germans), and are disposed in veins, nests, and grains. When the opal adheres in small particles closely together in the stone, it forms what is called mother of opal. It is found in the same manner in a kind of breccia of this decomposed porphyry. (Townson's Travels in Hungary, p. 327.) It is found also at Leibnitzstock, Johann-Georgenstadt, and Freyberg in Saxony. At this latter place the repository of the opal is porphyry. The opal also is met with in Iceland.

The opal mines described by Dr Townson are situated in a hill of some miles in extent not far from the village of Czerwenitz. This hill has been opened in several places, but in three with the greatest success. Guards are placed upon it to prevent any person from digging this precious stone; for as it is situated in part of the royal domain, the peasants who were formerly permitted to search for it on their own account are now prohibited by the emperor. But even at the time Dr Townson visited the mines the work had been discontinued for three or four years as unprofitable. The usual mode of conducting the operations in searching for the opal is by quarrying to the depth of three or four yards, rarely deeper. The rock is thus thrown out, broken to pieces, and afterwards examined. In one place the search had been made by mining; but the gallery was only a few yards in length. From this account it appears that the rock containing the opal lies near the surface, and seldom, it is said, extends deeper than a few fathoms. The opals denominated oriental by the lapidaries, a term expressive of their value rather than of their origin, are supposed to be from these mines, in which, according to records still in existence, 300 men were employed not less than 400 years ago.

Uses.—On account of the fine play of colours, the opal is held in great estimation for the purposes of jewellery, and the opals which reflect green colours in most abundance are most highly valued. The finest opals are called oriental; but this epithet is given by the lapidaries to the more perfect precious stones, and is not to be understood as denoting that they have been brought from eastern countries. The ancients, it would appear from the account of Pliny, attached an immense value to this stone; for he informs us that a senator called Nonius rather submitted to banishment than give up an opal which he had in his possession to Mark Anthony. This opal was estimated at 20,000 sesterces. Lib. xxxvii. cap. 6.

Subspecies 2. COMMON OPAL.

Semi-opal, Kirwan, i. 290. L'Opale Commune, Brochant, i. 344. Quartz refinite Hydrophane et Quartz-refinite Girafoi, Hauy, ii. 433.

Exter. Char.—Common opal is found in masses, or disseminated, sometimes in rounded or angular pieces, and sometimes kidney-shaped or botryoidal. Internal lustre splendid, and intermediate between vitreous and resinous. Fracture conchoidal, but sometimes uneven. Fragments sharp-edged.

Colour milk-white, and varieties of this colour held in certain directions appear of a wine yellow. The other shades of colour are yellowish or reddish white, and wax or honey yellow. Semitransparent and sometimes transparent. Specific gravity from 1.958 to 2.015. In other characters the same as the precious opal.

Chem. Char.—Insoluble before the blow-pipe, but melts with borax and without frothing up.

Constituent Parts. Klaproth.

| From Kuzemutzy | From Telkobanya | |----------------|----------------| | Silica, | Silica, | | 98.75 | 93.50 | | Alumina, | Oxide of iron, | | 0.10 | 1.00 | | Oxide of iron, | Water, | | 0.10 | 5.00 | | Lofs, | Lofs, | | 1.05 | |

Localities, &c.—The common opal is found in veins, chiefly in amygdaloid rocks, and sometimes also, it is said, in granites and porphyries. It is of most frequent occurrence in Bohemia; in Saxony, as at Freyberg, Eibenstock, &c.; in Hungary, in Poland, in Scotland, and the Faroe islands. The amygdaloid rocks in the vicinity of the Giants Causeway in the north of Ireland also afford a repository for this mineral.

Uses.—It is employed as well as the former for the purposes of jewellery, but is esteemed of inferior value.

It has been observed of some varieties of common opal that they are hydrophanous, that is, they possess the property of becoming transparent when immersed in water, a property which it is supposed depends on the absorption of the water in the pores of the opal. When similar varieties of opal are dipped in melted wax, they are impregnated with it, and become in like manner transparent, but on cooling resume their opacity. To such varieties De Born has given the name of Pyrophane.

Subspecies 3. SEMI-OPAL.

Id. Kirwan, i. 290. La Demi-opale, Brochant, i. 347. Quartz Refinite Commune, et Menilite, Hauy, ii. 433.

Exter. Char.—This mineral is found in masses or disseminated, in angular fragments, stalactitical, botryoidal, or in superficial layers. Lustre glimmering or shining, and intermediate between vitreous and resinous. Fracture conchoidal, and frequently even. Fragments sharp edged.

Colours extremely various, but in general duller and less vivid than common opal. The most predominant are yellowish, grayish and reddish white, more rarely milk white. Various colours are sometimes disposed in spots, stripes, and clouds. Translucent at the edges, and sometimes, but rarely, semitransparent. Pretty hard and brittle. Spec. grav. 2.540.

Chem. Char.—Insoluble before the blow-pipe, but melts with borax and without frothing up.

Constituent Parts. Klaproth.

| Silica, | 43.50 | | Oxide of iron, | 47.00 | | Water, | 7.50 | | Lofs, | 2.00 |

Localities, &c.—The semi-opal is found in the same places and in similar rocks with the common opal, as in bafalt and amygdaloid, but chiefly in granite and porphyry, and particularly in the veins of such rocks containing silver.

Some varieties of pitch stone have been ranked with semi-opal by mineralogists; and menilite, a mineral to be afterwards described, has been also considered merely as a variety of it.

Subspecies 4. WOOD OPAL.

Ligniform Opal, Kirwan, i. 295. Opale Ligniforme, Brochant, i. 350. Quartz refinite Xyloide, Hauy, ii. 439.

Exter. Char.—This variety of opal is found in masses of different sizes, retaining the form and texture of the wood which is supposed to be penetrated with the stony opaline matter. Lustre internally weakly shining, between vitreous and resinous. Transverse fracture conchoidal, longitudinal fracture shows the woody texture. Fragments sharp-edged.

Colours grayish and yellowish white, yellowish brown and ochre yellow. Different colours are sometimes arranged in concentric circles, in spots, and stripes. Often opake, but rarely translucent except at the edges. Intermediate between hard and semi-hard. Brittle. Spec. grav. 2.600.

Localities, &c.—The wood opal is found at Pornick near Schemnitz in Hungary, and at Telkobanya in the same country.

34. Species, MENILITE.

Pitchstone, Kirwan, i. 292. Variety of flint of some, and Semi-opal of Klaproth.

Exter. Char.—This mineral is found in tubercle masses, which have a smooth ribbed surface, and are sometimes covered with a whitish crust. Internal lustre weakly shining. Transverse fracture flat, conchoidal; longitudinal, coarse, splintery. Fragments sharp edged. Chestnut brown colour, and marked with alternating stripes of pearl gray and reddish brown. Translucent. Pretty hard and brittle. Spec. grav. 2.185.

Constituent... **MINERALOGY**

**Constituent Parts**, Klaproth.

| Silica | 85.50 | |-----------------|-------| | Alumina | 1 | | Oxide of iron | .50 | | Lime | .50 | | Water and carbonaceous matter | 11.50 | | Loes | 1 |

Total: 100.00

**Localities, &c.—** This mineral is found at Menil-Montant, from which it derives its name, near Paris, in nodules disposed in interrupted strata, in the middle of a foliated, argillaceous schistus, which is interposed between the beds of gypsum.

35. Species. JASPER.

Jasper has been divided into six subspecies, 1. Egyptian; 2. Striped; 3. Porcelain; 4. Common; 5. Agate; and, 6. Opal.

Subspecies 1. EGYPTIAN JASPER.

*Egyptian Pebble*, Kirwan, i. 312. *Le Jaspe Egyptien*, Brochant, i. 332.

**Exter. Char.—** This variety of jasper is found in rounded pieces, which are generally spherical, and have a rough surface. External lustre glimmering or weakly shining; internal weakly shining. Fracture perfect conchoidal; fragments sharp-edged.

The colours of this variety are disposed in zones or irregular stripes, which are nearly concentric. These colours are yellowish brown on a ground of chestnut brown; usually opaque, or slightly translucent at the edges. Spec. grav. 2.56 to 2.6.

**Chem. Char.—** Infusible before the blow-pipe.

**Localities, &c.—** This mineral, as its name imports, is brought from Egypt, where, as was observed by Cordier, it constitutes part of a breccia which is entirely composed of fragments of siliceous stones, immense strata of which abound in that country, and the deserts of Africa in the vicinity. The masses of jasper are found among the sand which has been derived from the decomposition of this breccia, and particularly near Suez.

**Uses.—** This variety, on account of its hardness and beautiful colours, is in considerable estimation for ornamental purposes.

Subspecies 2. STRIPED JASPER.

*Id. Kirw. i. 312. Le Jaspe Rubané*, Broch. i. 334. *Quartz-Jaspe Onyx*, Hauy, ii. 436.

**Exter. Char.—** This variety of jasper is found massive, and sometimes forms entire beds. It has no lustre, except from the mixture of extraneous substances. Fracture conchoidal, sometimes splintery or earthy. Fragments sharp-edged.

To the variety of colours of this mineral it owes its name. These are pearl gray, yellowish and greenish gray, with shades of red and blue, and these different colours are arranged in straight or curved lines; generally opaque, translucent only at the edges.

**Localities, &c.—** This variety of jasper abounds in Siberia; it is found also in Saxony, in the Hartz, where it repose on gray wacken; in Sicily; and in the hills in the vicinity of Edinburgh.

Subspecies 3. PORCELAIN JASPER.

*Porcellanite*, Kirw. i. 313. *Le Jaspe Porcelaine*, Broch. i. 336. *Thermantide Porcellanite*, Hauy, iv. 510.

**Exter. Char.—** Usually found in masses or angular pieces, in which rents or fissures are often observed, and also in whole beds. Internal lustre glimmering or weakly shining; resinous. Fracture imperfect conchoidal or uneven. Fragments sharp-edged.

The colour exhibits great variety; pearl, ash, yellowish and bluish gray, with shades of yellow, red, and rarely green. The colour is generally uniformly the same, but sometimes it is striped and dotted, flamed and clouded; impressions of vegetables of a red colour are observed on the blue varieties, and the rents or fissures are of a red colour in the grayish specimens; is entirely opaque; pretty hard, and easily frangible.

**Chem. Char.—** Melts before the blow-pipe into a black flag.

**Constituent Parts.**

| Rose. | |-------------| | Silica | 60.75 | | Alumina | 27.27 | | Magnesia | 3 | | Potash | 3.66 | | Oxide of iron | 2.50 | | Loes | 2.82 |

Total: 97.18

**Localities, &c.—** This mineral is abundant in different parts of Bohemia; it is met with also in Saxony, in the rocks in the vicinity of Edinburgh, and on the coast of Fife near Dysart in Scotland.

This jasper derives its name from its fracture, which resembles that of porcelain; and as it is frequently found in places where subterraneous fires have existed, such as beds of coal which have been kindled by accident, it is ascribed to their action; and according to Werner, it is nothing more than a flat clay altered by fire.

Subspecies 4. COMMON JASPER.

*Id. Kirw. i. 310. Jaspe Commun*, Broch. i. 338.

**Exter. Char.—** This variety is usually found massive, sometimes disseminated, or alternating in thin layers with other stones. Lustre glimmering or shining, between vitreous and resinous. Fracture more or less perfectly conchoidal, sometimes splintery or earthy. Fragments sharp-edged.

Colours extremely various, exhibiting different shades of red, yellow, and black; and several of these are united together, presenting clouds, spots, and stripes. Usually opaque, or slightly translucent at the edges. Is scratched by quartz. Easily frangible. Spec. grav. 2.3 to 2.7.

**Chem. Char.—** Entirely infusible before the blow-pipe. Siliceous pipe. Its constituent parts are extremely variable. The following were obtained by the analysis of Kirwan.

| Silica | 75 | |--------|----| | Alumina| 20 | | Oxide of iron | 5 |

Localities, &c.—This jasper is very common in different parts of the world; in Saxony, Bohemia, Hungary, France, Spain, Italy, Siberia, and also in Scotland, as among the basaltic rocks in the vicinity of Edinburgh, and at Dunbar. It is usually found in veins, especially such as contain ores of iron. It is often traversed with veins of quartz, or mixed with pyrites, lithomarga, semi-opal, brown spar, native and vitreous silver. It has been taken for the basis of some porphyries, but these turn out to be indurated clay, pitch stone, and horn stone.

Subspecies 5. Jasper Agate.

Exter. Char.—This variety seems to be the same as that already mentioned under the name of agate jasper, in speaking of agates at the end of the description of calcedony. It is found massive, and possesses no lustre. Fracture conchoidal, generally opaque, pretty hard, and sometimes adheres to the tongue. The colours are yellowish or reddish white, which are disposed in stripes and circles.

Localities, &c.—It is met with in many places in agate balls, in amygdaloid rocks.

Subspecies 6. Opal Jasper.

Exter. Char.—This variety of jasper seems to possess many common characters with some varieties of opal. It is found massive. Internal lustre between vitreous and resinous, is shining or repellent. Fracture conchoidal. Fragments very sharp-edged.

Colours scarlet red, blood red, brownish red, more rarely yellow. Colours disposed in veins, spots, and clouds. Opaque, or translucent at the edges. Brittle, and easily frangible.

Localities, &c.—This mineral is found in Hungary, in Siberia, and other places, and is usually in nests in porphyry.

Beside the localities of the different varieties of jasper already mentioned, we may notice that it is met with in Siberia of a white and bluish colour. The hill on which the fortress of Orskai stands on the left bank of the river Jaik, in the government of Orembourg, is entirely composed of a pale green and deep red jasper, disposed in inclined beds; and on the most elevated parts of the Altaian mountains, near the source of the river Korgou, a jasper has been discovered of an ivory white colour, which is remarkable for being penetrated with black dendrites.

Uses of Jasper.—It is valued according to its hardness, the degree of polish of which it is susceptible, and the beauty and variety of its colours; and it is employed in forming vases, handles for swords and knives, and other smaller ornamental purposes.

36. Species. Heliotrope, or Bloodstone.

Heliotropium, Kirw. i. 314. L'Heliotrope, Broch. i. 276. Quartz jaspe Sanguin, Hauy, ii. 436.

Exter. Char.—Heliotrope is found massive or in angular pieces; external lustre glimmering or shining, and resinous; fracture conchoidal, sometimes uneven. Fragments very sharp-edged.

Colour chiefly deep green, but of various shades, with spots of olive and yellow, but most frequently scarlet or blood red; translucent at the edges; hard, easily frangible. Spec. grav. 2.62 to 2.7.

Chem. Char.—Entirely infusible before the blow-pipe.

Localities, &c.—This mineral was originally brought from the east, but it has since been found in Siberia, in Bohemia, where it is met with in a vein, and in Iceland.

Uses.—It is employed for similar purposes with jasper or agate.

By many mineralogists this mineral is considered as a variety of jasper; hence it has been called oriental jasper; and it is supposed by some to be a calcedony penetrated with green earth.

37. Species. Chrysoprase.

Chrysoprasium, Kirw. i. 284. La Chrysoprase, Broch. i. 285. Quartz Agathe Prae, Hauy, ii. 426.

Exter. Char.—This mineral is found massive, or in angular fragments; internal lustre rarely glimmering; fracture even, sometimes splintery; fragments sharp-edged.

Colour apple-green, greenish gray, or leek-green; translucent, sometimes semitransparent; less hard than calcedony and flint. Spec. grav. 2.25.

Chem. Char.—Infusible before the blow-pipe, but loses its transparency, and becomes white.

Constituent Parts. Klaproth.

| Silica | 96.16 | |--------|-------| | Alumina| .58 | | Lime | .82 | | Oxide of iron | .88 | | Oxide of nickel | 1.00 | | Loes | 1.86 |

Localities, &c.—Chrysoprase is found at Kofemutz, in Upper Silesia, in a mountain composed of serpentine, asbestos, indurated talc, and lithomarga.

Uses.—It is employed for similar purposes as jasper, and it is greatly esteemed when it is of a fine apple-green colour. It is said that some varieties of this mineral lose their colour by being exposed to moisture, so that the jewellers, before using them, put them to the test, by keeping them for some time in a moist place.

38. Species. Plasma.

Id. Broch. i. 278. Silex Plaume, Brongniart, ii. 398.

Exter. Char.—This mineral is found disseminated, in rounded pieces, and also in angular pieces. Internal lustre glimmering or weakly shining; resinous. Fracture conchoidal, even, and sometimes splintery. Translucent, and sometimes even transparent in thin pieces.

Colour, various shades of green; and sometimes different colours are disposed in spots, stripes, and points. Nearly. Nearly equally hard with calcedony. Brittle, and easily frangible.

Chem. Char.—It is infusible before the blow-pipe, but becomes white.

Localities, &c.—It is said by some, that this mineral has only been found among the ruins of Rome, but according to Bronniart and others, it has been found in the Levant, in Upper Hungary, and in Moravia, in a mountain of serpentine, where it is accompanied with flint.

Uses.—It appears that this mineral was much employed by the ancients for ornamental purposes.

39. Species. Cat's Eye.

Id. Kirw. i. 301. L'Oeil de Chat, Brochant, i. 292. Quartz-Agathe Chatoyant, Hauy, ii. 427.

Exter. Char.—This mineral, as it is brought from its native country, is usually cut and polished, so that its natural form is unknown; but it is supposed that it is met with in grains or rounded pieces. A mass described by Klaproth, which seemed to be in its natural state, had a quadrangular form, a rough surface, and considerable brilliancy. The lustre is resplendent and resinous. The cross fracture is uneven, the longitudinal fracture imperfectly foliated. Fragments more or less sharp-edged.

The colour is greenish yellow and smoke gray, of various shades, and sometimes, but rarely, grayish or silvery white. It is translucent, rarely semitransparent. When it is cut, it reflects different rays of light by changing its position, a character by which it is easily known. This is ascribed to small parallel fibres which appear in the interior of the stone. It is hard, easily frangible. Spec. grav. 2.625 to 2.660.

Chem. Char.—It melts with great difficulty by the action of the blow-pipe. Klaproth subjected it to the heat of a porcelain furnace, but it was not melted; it only lost its hardness, lustre, and transparency, and the colour became of a pale gray.

Constituent Parts. Klaproth.

| Silica | Alumina | Lime | Oxide of iron | Loes | |-------|---------|------|--------------|-----| | 95.00 | 1.75 | 1.50 | 0.25 | 1.50|

Localities.—Cat's eye is brought from Ceylon and the Malabar coast, and also, it is said, from Egypt and Arabia; but always in the polished state. The only one known in its natural state was that above mentioned, which was presented to Klaproth by Mr Greville of London.

Uses.—This mineral is in great estimation as a precious stone, and it is usually cut for ring-stones.

The name is derived from its possessing the property of reflecting the light similar to the eye of the cat, and hence the term chatoyant among jewellers, which is expressive of that effect.

49. Species. Obsidian.

Id. Kirwan, i. 265. Iceland agate vulgo, L'Obsidienne, Brochant, i. 288. Lave vitreuse Obsidienne, Hauy, iv. 594.

Exter Char.—This mineral is found in masses, and sometimes in rounded pieces. Lustre resplendent, vitreous; fracture perfectly conchoidal; fragments very sharp-edged.

The most common colour of obsidian is perfectly black, sometimes greenish and grayish, black, blueish, greenish and smoke gray, and yellow and red, according to Humboldt: most commonly opaque, but sometimes translucent on the edges. It is hard and easily frangible. Spec. grav. 2.348.

Chem. Char.—Before the blow-pipe obsidian melts into an opaque porous glass, of a grayish white colour.

Constituent Parts.

| Bergman. | Abilgaard. | |----------|-----------| | Silica | 69 | 74 | | Alumina | 22 | 12 | | Oxide of iron | 9 | 14 |

100 100

| Descottis. | Drappier. | |------------|-----------| | Silica | 72.0 | 74.0 | | Alumina | 12.5 | 14.0 | | Lime | 1.2 | 1.6 | | Oxide of iron and manganese | 2.0 | 3.0 | 4.0 | | Potash and soda | 10.0 | 3.3 | 4.0 | | Loes | 3.5 | 4.5 |

100.0 100.0 100.0

Localities, &c.—This mineral is found in Iceland, in Siberia, in the Lipari islands, in Hungary, in Madagascar, the island of Teneriffe, in Mexico, Peru, and some of the South sea islands. Humboldt discovered a variety of obsidian in New Spain, which was chatoyant in a considerable degree. The obsidian from Hungary is found in inflated pieces among detached masses of granite, gneiss and decomposed porphyry. Obsidian was long supposed to have a volcanic origin; but it appears from the accounts of those who have visited Iceland, that it is not only found in the vicinity of Hecla, but everywhere, distributed like quartz and flint; and besides it is not unfrequent in countries where volcanoes were never known to exist.

Uses.—The fine colour and hardness of this stone have brought it into use for ornamental purposes. Among the ancient Mexicans and Peruvians it was employed as mirrors, some of which, it is said, are sometimes still found in the tombs of their ancient sovereigns (Faujas Miner. des Volcans, p. 308.) and also for cutting instruments as knives and even razors. Hernandez saw the Mexican cutlers make a hundred knives of obsidian in the course of an hour. Obsidian, it is said, has also been used as mirrors for telescopes.

41. Species. Pitchstone.

Id. Kirwan, i. 292. La pierre de poix, Brochant, i. 353. Petroflex resiniforme, Hauy, iv. 386.

Exter Char.—Pitchstone, which has received its name name from its resemblance to pitch, is found massive; sometimes in extensive beds and veins, and also forming entire mountains. Internal lustre shining and resinous, Fragments sharp-edged. In coarse and frequently small granular distinct concretions which have a smooth surface.

The colours are various shades of black, green, brown, red, and gray. Translucent, but commonly at the edges only. Brittle, and rather easily frangible. Spec. grav. of pitchstone from Saxony, 2.314; of black pitchstone from Arran, 2.338; of pitchstone from Meissen, 1.645, Klaproth.

Chem. Char.—Fusible by the blow-pipe, and is converted into a white porous enamel.

Constituent Parts of pitchstone from Meissen of an olive green colour. Klaproth, Transl. ii. 207.

| Silica | 73 | |--------|----| | Alumina | 14.50 | | Lime | 1 | | Oxide of iron | 1 | | Oxide of manganese | 0.10 | | Soda | 1.75 | | Water | 8.50 | | Loes | 1.5 |

100.00

Localities, &c.—Pitchstone is found in great abundance in Saxony, in Hungary, and also in Siberia. It abounds also in Scotland, particularly in the island of Arran, where it is met with in beds, but chiefly in veins traversing the strata in the less elevated parts of the island. Pitchstone also forms the basis of a porphyry.

42. Species. PEARLSTONE.

Obsidienne Perlée, Brongniart, ii. 340. Lave Vitreuse Perlée, Hauy, iv. 495. Volcanic Zeolite, Fichtel. Zeolitic Pitchstone of others. See Klaproth, Transl. ii. 263.

Exter. Char.—Pearlstone almost always forms the ground or basis of a species of porphyry which contains roundish or lengthwise vesicular cavities. Lustre pearly. Fracture seems imperfectly conchoidal; but is not very perceptible. Fragments blunt-edged.

Colour bluish, ash, greenish gray. Translucent at the edges. When breathed upon gives out the argillaceous odour. Not brittle, but easily frangible. Soft. Spec. grav. 2.340 to 2.548.

Chem. Char.—Before the blow-pipe froths up like zeolite, but is not fused.

Constituent Parts. Klaproth, ii. 267.

| Silica | 75.25 | |--------|------| | Alumina | 12 | | Oxide of iron | 1.60 | | Lime | .50 | | Potash | 4.50 | | Water | 4.50 | | Loes | 1.65 |

100.00

Localities, &c.—Pearlstone is found near Tokay in Hungary, in strata alternating with those of argillaceous porphyry, and containing in its vehicles nodules of obsidian; it is also met with in Iceland, and in the north of Ireland.

43. Species. PUMICE.

Id. Kirwan, i. 415. La Pierre ponce, Brochant, i. 443. Ponce, Brongniart, i. 332. Lave vitreuse pumicee, Hauy, iv. 495.

Exter. Char.—This mineral is found massive or disseminated, and it is always of a porous or vesicular texture.

Lustre glimmering, or a little shining and silky. Fracture fibrous; fragments blunt-edged.

Colour greyish white, bluish, or yellowish gray. Opaque, rarely translucent at the edges, sometimes semihard, but generally soft, very brittle, and very easily frangible. Spec. grav. 0.914.

Chem. Char.—Fusible before the blow-pipe, and is converted into a white glass.

Constituent Parts. Klaproth, ii. 208.

| Silica | 77.50 | |--------|------| | Alumina | 17.50 | | Oxide of iron | 1.75 | | Soda of potash | 3 | | Loes | .25 |

100.00

Localities, &c.—Pumicestone has been supposed to be a volcanic production, because it is found in the vicinity of volcanoes; the Lipari islands are almost entirely composed of it, and there it is accompanied with obsidian. It is also found in Iceland and Teneriffe; in Hungary; and on the banks of the Rhine between Andernach and Coblentz.

Use.—Pumice is very much employed in polishing stones, metals, glass, ivory, and in the preparation of parchment.

A rare variety of pumice is described by Brongniart in the form of vitreous filaments as fine as hair; the colour is a deep bottle green, and it melts by heat into a white enamel. This pumice is supposed to be projected from the volcano in the Isle of Bourbon.

44. Species. PREHNITE.

Id. Kirwan, i. 274. La Prehnite, Brochant, i. 295. Prehnite, Hauy, iii. 67.

Effin. Char.—Divisible by one distinct line only, and pretty clean; elastic by heat.

Exter. Char.—Prehnite is found either massive or crystallized. The principal form of its crystals is a four-sided rhomboidal table, which is either perfect or truncated on all its edges, or a table with six faces, and an equal angle, or a large rectangular prism terminated by a bevelment which is somewhat obtuse. The crystals are usually grouped together, and united by their lateral faces; face of the crystals smooth; external lustre shining; internal weakly thinning and pearly; principal fracture foliated, cross fracture fine-grained uneven; fragments but little sharp-edged. Colour green, olive green, mountain green, and greenish white; semitransparent, and sometimes transparent. Scratches glass slightly. Brittle, and easily frangible. Spec. grav. 2.699 to 2.696.

Chem. Char.—Fusible before the blow-pipe, into a white porous enamel.

Constituent Parts.

| Constituent Parts | Meyer | |-------------------|-------| | Silica | 41 | | Alumina | 31 | | Lime | 11 | | Water | 15 | | Lofs | 2 |

Localities.—Prehnite was brought first from the Cape of Good Hope, by Colonel Prehn, whose name it now bears. It is also found in France, as in Dauphiny, where it exists in veins. It is not unfrequent in different parts of Scotland, as among the porphyry rocks six miles to the south of Peebles; in the neighbourhood of Dunbarton; and in the rocks round Edinburgh.

45. Species. Zeolite.

This species has been divided into four subspecies.

Subspecies 1. Mealy Zeolite.

Zeolite, Kirwan, i. 278. La Zeolite Farineuse, Brochant, i. 298. Mefotype, Hauy, iii. 151.

Exter. Char.—This variety is found massive or disseminated, and sometimes it is branched or coralloid, and sometimes also it envelopes other zeolites with a thin crust. It is dull; fracture earthy; fragments blunt-edged.

Colour usually reddish or yellowish white, or flesh red, opaque, very brittle; does not adhere to the tongue. When scratched with the finger nail it gives out a dull sound.

Constituent Parts.

| Constituent Parts | Pelletier | |-------------------|-----------| | Silica | 50 | | Alumina | 20 | | Lime | 8 | | Water | 22 |

Localities, &c.—This variety of zeolite is found in Ireland, the Faro islands, and Sweden. It is frequent in different parts of Scotland, as at Dunbar, and several of the Western islands.

Subspecies 2. Fibrous Zeolite.

Zeolithe Fibreuse, Brochant, i. 299. Mefotype, Hauy, i. 151.

Exter. Char.—This variety is found massive, and sometimes in rounded pieces, composed of capillary crystals, divergent and radiating; internal lustre glimmering, or weakly shining, pearly or silky; fracture fibrous; fibres divergent; fragments wedge-shaped.

Colour yellowish white, yellowish brown, snow white, and sometimes honey yellow, translucent; semifluid, brittle, and easily frangible. Light.

Constituent Parts.

| Constituent Parts | Vauquelin | |-------------------|-----------| | Silica | 50.24 | | Alumina | 29.30 | | Lime | 9.46 | | Water | 10. | | Lofs | 1. |

Subspecies 3. Radiated Zeolite.

Zeolithe Rayonnée, Brochant, i. 301. Mefotype, Hauy, iii. 151.

Exter. Char.—Divisible parallel to the faces of a rectangular prism; electric by heat in two opposite points.

Exter. Char.—This variety is found massive, but most frequently crystallized: the primitive form is a rectangular prism with square bases; its common forms are a rectangular prism, truncated at each extremity by a four-sided pyramid, corresponding to the lateral faces; a four-sided rectangular prism with two broad and two narrow sides, and also terminated by four-sided pyramids, or a four-sided prism, nearly rhomboidal, the two sharp lateral edges of which, as well as the two obtuse terminal angles, are truncated. The crystals are united together in bundles; so that the acuminations only can be seen; the crystals are commonly smooth and shining; the internal lustre is weakly shining and pearly; fracture radiated; the rays broad or narrow; fragments wedge-shaped.

Colour yellowish, grayish, reddish, and snow-white; translucent, sometimes transparent; semifluid; scratches calcareous spar; brittle, and easily frangible. Spec. grav. 2.0833.

Chem. Char.—Before the blow-pipe it froths up, gives out a phosphorescent light, and is converted into a porous enamel. With acids it forms a gelatinous substance.

Subspecies 4. Foliated Zeolite.

Zeolithe Lamelleuse, Brochant, i. 302. Stilbite, Hauy, iii. 161.

Exter. Char.—Fusible into a spongy enamel, but not electric by heat.

Exter. Char.—This variety of zeolite is usually found in amygdaloidal or globular pieces, and also crystallized; primitive form of its crystals is a rectangular prism with rectangular bases: the usual forms of its crystals are, are, a short equiangular six-sided prism with two broad, two narrower, and two very narrow faces; a table with six equal faces, and a rhomboidal prism. Surface of the crystals smooth and shining; internal lustre shining and pearly; fracture foliated; the plates most frequently curved with a simple cleavage.

Colour similar to the former; it is translucent or semitransparent; semihard, and easily frangible. Spec. grav. 2.5.

Chem. Char.—Froths up and phosphoresces, under the blow-pipe; placed on hot coals, it becomes white and is easily reduced to powder. It is not converted into a jelly by acids.

**Constituent Parts.** Vauquelin.

| Silica | 52 | |--------|----| | Alumina| 17.5 | | Lime | 9 | | Water | 18.5 | | Lofs | 3 |

100

Localities, &c.—The different varieties of zeolite are usually found in amygdaloid rocks, basalts, porphyry, slate, wacken, and green stone. They often line the sides of fissures passing through these rocks, and are accompanied with calcareous spar, calcedony, sometimes with native copper and native silver, as in Iceland. The finest zeolites are brought from the islands of Faroe, Iceland, Ædelforss in Sweden. The different varieties are not unfrequent in Scotland. The fibrous and radiated kinds are met with extremely beautiful in the islands of Cannay and Skye; the foliated or fillbite in the island of Staffa, in Skye, and in the lead veins at Strontian.

46. Species. Cubizite.

La Zeolithe Cubique, Brochant, i. 304. Analcime, Chabafie, Hauy, iii. 180.

Efflen. Char.—Original forms of the cube, fusible into a glass.

Exter. Char.—This mineral is found massive or crystallized; the form of the crystals is a perfect cube, which is its primitive form. This is sometimes truncated on all its angles by three small triangular faces, or with twenty-four equal and similar trapezoids like the garnet. The external lustre is resplendent, vitreous, or pearly. Internal shining or weakly shining. Fracture imperfectly foliated, almost uneven. Fragments imperfect cubes.

Colour white, yellowish, grayish, or reddish white. It is translucent or opaque. Semihard. Spec. grav. about 2 (Hauy). Difficult to produce any signs of electricity; hence the name analcime, signifying want of power, given to it by Hauy.

Chem. Char.—Froths up before the blow-pipe, and melts into a porous glass.

Localities, &c.—Cubizite is found in Skye, in Staffa, and in the Salisbury rocks near Edinburgh. Fine specimens of cubizite are abundant at the Giants Causeway in the north of Ireland. Chabafie is found also at Oberstein in Germany.

By many mineralogists chabafie and analcime are considered as one species; but more nearly investigated, as has been done by Hauy and others, they must appear very different. The preceding description refers chiefly to analcime. We shall shortly state the principal characters of chabafie from Hauy, iii. 176.

Efflen. Char.—Divisible into a rhomboid slightly obtuse, and easily fusible by heat.

Exter. Char.—Chabafie is commonly crystallized. Primitive form of the crystals is a slightly obtuse rhomboid, whose plane angle at the summit is about 93°, so that it approaches nearly to the cube; integrant molecule is the same. Six of the edges are truncated, the truncations uniting three and three at the two opposite angles, and the remaining six angles are also truncated. It appears also in the form of double six-sided pyramids applied base to base, having the five angles at the base, and the three acute edges of each pyramid truncated.

Colour whitish, sometimes reddish, but this seems to be owing to a superficial crust. Lustre shining or resplendent and vitreous. Transparent or translucent.

Chem. Char.—Is easily fusible before the blow-pipe, and melts into a whitish spongy mass.

47. Species. Cross-stone.

Staurolite, Kirwan, i. 282. Pierre Cruciforme, Brochant, i. 311. Harmotome, Hauy, iii. 191.

Efflen. Char.—Divisible into a rectangular octahedron, which may be subdivided on the angles contiguous to the summits.

Exter. Char.—This mineral is always crystallized. Its usual forms are, a double crystal composed of two broad prisms, with four rectangular faces, and terminated at each extremity by a four-sided obtuse pyramid placed on the lateral edges. These two prisms cross each other by their broader faces, so that the faces of the acumination meet together, and the double crystal thus formed having four right-angled re-entering angles, resembles a cross. The crystals are obliquely streaked. External lustre shining and resplendent, vitreous. Internal weakly shining. Fracture foliated.

Colour grayish or milky white, translucent, sometimes semi-transparent. Semi-hard, scratches glass slightly. Spec. grav. 2.333 to 3.61.

Chem. Char.—Before the blow-pipe it is fusible, and froths up. The powder thrown on hot coals is phosphorescent, giving out a greenish yellow light.

**Constituent Parts.**

| Silica | 49 | |--------|----| | Barytes| 18 | | Alumina| 16 | | Water | 15 | | Lofs | 2 |

100

Localities.—This mineral has been found in veins at Andertenberg in the Hartz, accompanied by carbonate of lime, from which it is sometimes called andertonite. It is also found in the lead veins at Strontian in Scotland, and in balls of agate at Oberstein. In the latter place, crystals are single.

48. Species. 48. Species. LAUMONITE.

Zeolithe Efflorescente, Hauy, iv. 410. Id. Brochant, ii. 530.

Exter. Char.—This mineral is found in masses which are composed of irregular groups of crystals crossing each other in all directions. Form of the crystals is a four-sided prism, nearly rectangular, and terminated by a base inclined to one of the lateral edges under an angle of 133°; frequently the acute angle is truncated, and thus terminating in a bevelment placed on the acute lateral edges. The lateral faces are longitudinally streaked, and the lustre is shining. The faces of the summit are also shining, but smooth. Fracture foliated, and parallel to the lateral faces.

Colour grayish white, somewhat pearly. Is translucent, rather soft, sectile, and easily frangible.

But all these characters are considerably different by the action of the air. The whole mass is gradually separated, and the crystals become opaque, falling into friable fulia, which are in a short time reduced to a snow-white powder, from which it derives the name given to it by Hauy.

Chem. Char.—Fusible before the blow-pipe, without frothing up, into a white enamel, and forms a jelly with acids.

Localities.—This mineral was found in 1788 by Gillet Laumont, in the lead mines of Huelgoët in Brittany in France, and from him it derives its name. It forms a small vein contiguous to the vein of galena. We have collected specimens of a mineral, whose characters correspond with laumonite, in a vein traversing a basaltic rock in the island of Skye. After being kept for some years it appeared equally liable to disintegration by exposure to the air.

49. Species. DIPYRE.

Id. Brochant, ii. 508. Id. Hauy, iii. 242.

Efflen. Char.—Divisible parallel to the faces of a regular 6-sided prism. Fusible with intumescence.

Exter. Char.—This mineral is found in small fascicular masses or crystals. Lustre shining, vitreous. Longitudinal fracture foliated.

Colour grayish or reddish white, and sometimes pale rose red. Semi-hard; scratches glass, and is easily frangible. Spec. grav. 2.630.

Chem. Char.—Fusible. The powder thrown on hot coals produces phosphorescence.

Constituent Parts. Vauquelin.

| Silica | 60 | |--------|----| | Alumina| 24 | | Lime | 10 | | Water | 2 | | Lofs | 4 |

100

Localities, &c.—This mineral has only been found at Mauléon, in the Pyrenees, in a rock of fleatites. It was discovered by Lelièvre and Gillet Laumont, in 1786.

50. Species. NATROLITE.

Id. Klaproth. Id. Brongniart, i. 370.

Exter. Char.—This mineral is found in masses, in a rock of amygdaloid. External surface somewhat rough; internal lustre glimmering; fracture fibrous and radiated.

Colour brownish yellow, inclining to olive, and different colours appear in parallel and waved zones; is translucent at the edges; scarcely scratches glass; is easily frangible. Sp. grav. 2.16.

Chem. Char.—Is reduced by the blow-pipe to a white glass. Nitric acid produces no effervescence, but converts it in a few hours to a thick jelly.

Constituent Parts. Klaproth.

| Silica | 48 | |--------|----| | Alumina| 24 | | Soda | 16 | | Water | 9 | | Oxide of iron | 1.75 | | Lofs | 1.75 |

100.00

Localities, &c.—Natrolite has been found only at Roegau, near the lake of Constance in Switzerland, in the cavities of an amygdaloid rock. The name is derived from natron or soda, of which it contains so large a proportion.

51. Species. AZURITE.

Lazulite, Klaproth, Analyt. Essays, i. 170. Le Lazulithe, Broch. i. 315.

Exter. Char.—This mineral has been found disseminated, massive, and crystallized in rectangular four-sided prisms. Lustre glimmering and shining. Fracture imperfectly conchoidal.

Colour indigo, Prussian, or deep smalt blue; streak lighter blue; nearly opaque, or translucent at the edges; hardness, nearly that of quartz. Brittle and easily frangible.

Chem. Char.—Infusible before the blow-pipe, but loses its colour, becomes earthy, and of a clear gray. With borax it produces a bright yellow glass. Acids have a very feeble action upon it. Klaproth ascertained that it is composed of silica, alumina, and oxide of iron; but the quantity which he operated on was too small to ascertain the proportions.

Localities, &c.—This mineral has been found at Vorau in Styria, in a rock of micaceous schistus, where it forms, along with grayish quartz and silvery white mica, a vein of about half an inch thick.

52. Species. LAZULITE.

Lapis Lazuli, Kirw. i. 283. La Pierre d'Azure, Broch. i. 313. Lazulithe, Hauy, iii. 145.

Exter. Char.—This mineral is found massive, disseminated, and in rounded fragments; internally dull, and rarely glimmering. Fracture earthy, or fine-grained uneven; fragments sharp-edged.

Colour Colour azure blue; opaque, or translucent on the edges; hard, or semihard; brittle and easily frangible.

Spec. grav. 2.76 to 2.94.

Chem. Char.—It retains its colour at the temperature of 100° Wedgewood; but with stronger heat froths up into a yellowish hard coloured mass. By increasing the heat, it changes to a white enamel; with acids after calcination, forms a jelly.

Constituent Parts

| Klaproth. Analyt. Eff. i. 169. | |-----------------------------| | Silica, | 46 | | Alumina, | 14.5 | | Carbonate of lime, | 28 | | Sulphate of lime, | 6.5 | | Oxide of iron, | 3 | | Water, | 2 | | | 100.0 |

Localities, &c.—This mineral is found in Persia, Natolia, and China, and it is supposed that its repository is among granite. It has been found also in Siberia, near the lake Baikal, where it forms a vein along with garnets, feldspar, and gyrites. It is frequently mixed with pyrites, and a grayish white feldspar.

Uses.—This stone, when it is of a fine blue colour, and free from white spots, is held in great estimation for various ornamental purposes; but it derives its greatest value from its use in painting. The colour which it furnishes is called ultramarine. To prepare it, the stone is first calcined, and then reduced to an impalpable powder, which is mixed with a paste composed of resinous matters, of wax and linseed oil. From this mixture a powder is obtained by washing, which being dried affords the colouring matter. This colour, when used in painting, is not susceptible of change.

53. Species. Hydrargillite.

Wavellite of Dr Babington and others.

Exter. Char.—This mineral is found crystallized. The crystals are very minute, and are attached to quartz, in tufts or bundles, which diverge from a common centre. It is also found closely compacted together, in the form of mammillary protuberances of the size of small peas, and adhering to each other. The crystals, when magnified, appear to be four-sided, and, when broken, the section seems to be rhomboidal. The crystals have sometimes the appearance of fine down, and sometimes are of the size of a hair. Lustre silky.

The colour is white, with a shade of gray or green; usually opaque, and sometimes semitransparent. The texture is loose; but the small fragments are so hard as to scratch agate. Spec. grav. 2.25 to 2.70.

Chem. Char.—Infusible before the blow-pipe; but the crystals, exposed suddenly to strong heat, decrepitate.

Constituent Parts

| Davy, Nicholson Jour. xi. 153. | |-----------------------------| | Alumina, | 70 | | Silica, | - | | Lime, | 1.4 | | Oxide of iron, | - | | Water, | 26.2 | | A portion of fluorine acid, | - |

Localities, &c.—This mineral was first discovered by Dr Wavell, in a quarry near Barnstaple. Mr Hatchett found it, in 1796, filling the cavities and veins of a soft argillaceous schistus. It has since been found in Stenna-Gwyn mine, in the parish of St Stephen's, Cornwall, where it is accompanied with sulphuric tin, copper, and iron.

54. Species. Andalusite.

Adamantine Spar, Kirwan, i. 337. Spath Adamantine, Bournon, Jour. de Phys. 1789. Feldspar Apyre, Hauy, iv. 362.

Exter. Char.—This mineral is found massive, and crystallized in rectangular four-sided prisms, the summits of which are obliterated. Lustre weakly shining and resinous. Longitudinal fracture foliated. Cross fracture a little splintery. Colour reddish brown or violet; translucent at the edges. Very hard; scratches quartz, and sometimes even spinelle. Difficultly frangible. Spec. grav. 3.165.

Chem. Char.—Infusible before the blow-pipe.

Localities, &c.—This mineral was first discovered by Bournon in the granitic rocks of Foroz, where it occupies a vein of common feldspar. It has been found also in Spain, where it enters into the composition of a granite. It is also met with in Aberdeenshire. When first discovered, it was supposed to be a variety of adamantine spar or corundum; but its inferior spec. grav. and the difference in the structure of its crystals, afford sufficient characteristic differences.

55. Species. Feldspar.

This species is divided into the five following subspecies: 1. Adularia. 2. Labradorite stone. 3. Common feldspar. 4. Compact feldspar. 5. Hollow spar.

Subspecies 1. Adularia.

Moonstone, Kirwan, i. 322. L'Adulaire, Brochant, i. 371. Feldspar Nacre, Hauy, ii. 656.

Exter. Char.—This mineral is found massive or crystallized. The forms of its crystals are, 1. A four-sided rhomboidal prism. 2. A perfect rhomb, more or less oblique. 3. A rectangular four-sided table, with oblique terminal faces. 4. A fixed prism. 5. A fixed table. Surface of the crystals smooth or longitudinally streaked. Lustre shining or resplendent. Internal lustre resplendent, vitreous, or pearly. Fracture foliated. Cleavage double. Fragments rhomboidal.

Colour yellowish, greenish, or milk-white; is sometimes times chatoyant. Is always translucent; sometimes fe- mitransparent. Hard; scratches common feldspar. Brittle, and easily frangible. Spec. grav. 2.500 to 2.561.

Chem. Char.—Adularia before the blow-pipe cracks and splits, and then melts into a white glass.

Constituent Parts.

| Vauquelin | Weitbrum | |-----------|----------| | Silica | 64 | | Alumina | 20 | | Lime | 2 | | Potash | 14 | | Magnesia | | | Oxide of iron | 1.40 | | Sulphate of barytes | 2. | | Water | | | Lofs | 3.85 |

100.00

Localities, &c.—This mineral was first found by Pi- ni in one of the summits of St Gothard in Switzerland; this summit is called Adula, and from this it takes its name. It is said that it forms particular beds, inter- posed between micaceous schiltsus and gneiss. It is ac- companied with quartz, mica, and common feldspar.

Subspecies 2. LABRADOR STONE.

Id. Kirwan, i. 324. La Pierre de Labrador, Bro- chant, i. 369. Feldspath Opalin, Hauy, ii. 607.

Exter. Char.—This mineral is found massive, and in rounded pieces. Internal lustre shining, sometimes re- splendent; pearly, or vitreous. Fracture perfectly fo- liated, with a double cleavage.

Colour, most commonly dark or deep ash gray; but by varying its position it reflects different colours, as blue, green, yellow, brown, and red; and these colours exhibit stripes, spots, and dots. It is strongly translucent. Spec. grav. 2.6 to 2.7.

Chem. Char.—Before the blow-pipe fusible into a white enamel.

Constituent Parts. Bindheim.

| Silica | 69.5 | | Alumina | 13.6 | | Sulphate of lime | 12. | | Oxide of copper | .7 | | Oxide of iron | .3 | | Lofs | 3.90 |

100.00

Localities, &c.—This stone was first brought from the island of St Paul, near the coast of Labrador, whence its name. It has been since found in Bohemia, and near the lake Baikal in Siberia. It is rarely found in its native repository, but it is supposed to belong to pri- mitive rocks; for it is accompanied with schorl, mica, and hornblende.

Uses.—The brilliancy of its colours, and particularly its chatoyant property, have brought it into use in jewel- lery.

Subspecies 3. COMMON FELDSPAR.

Id. Kirwan, i. 316. Le Feldspath Commun, Brochant, i. 362. Feldspath, Hauy, ii. 590.

Exter. Char.—Feldspar is found massive, disseminat- ed, in rounded pieces, or crystallized. Its forms are, 1. A broad six sided prism with unequal angles, ter- minated at each extremity by an obtuse bevelment, whose faces are placed on the two lateral edges. 2. A four- sided rhomboidal prism. 3. A four-sided rectangular prism, having the lateral edges sometimes truncated; and, 4. A six-sided table. Double crystals are some- times met with. Lustre shining; internal lustre also shining, sometimes resplendent, vitreous or pearly. Fracture perfectly foliated; fragments rhomboidal.

Colours milk-white, yellowish, grayish, reddish, and greenish. Translucent; scratches glass; brittle, and easily frangible. Spec. grav. 2.437 to 2.704.

Chem. Char.—Before the blow-pipe melts into a white glass.

Constituent Parts.

| Vauquelin | Kirwan | Chenavix | |-----------|--------|---------| | Silica | 62.83 | 67 | | Alumina | 17.2 | 14 | | Lime | 3 | | | Oxide of iron | 1. | | Potash | 13 | | | Barytes | | 11 | | Magnesia | | 8 | | Lofs | 3.15 | |

100.00

Localities, &c.—Feldspar is one of the most common substances, and the most universally distributed in na- ture. It does not exist, however, in large masses. It forms one of the component parts of granite, gneiss, syen- ite and porphyry.

When exposed to the action of the air, it is very li- able to decomposition, and then it is converted into a white earthy mass, which is employed in the manu- facture of porcelain. This is the kaolin of the Chi- nese.

Subspecies 4. COMPACT FELDSPAR.

Continuous Feldspar, Kirw. i. 323. Le Feldpath Com- pacte, Broch. i. 367. Feldspath Compacte Bleu, Hauy, ii. 605.

Exter. Char.—This variety is found massive, and al- so in rounded pieces. Lustre weakly shining, or only glimmering. Fracture imperfectly foliated, sometimes splintery. Fragments not very sharp edged.

Colour bluish white, greenish or yellowish; translu- cent, but sometimes only at the edges. Streak white; it is scratched by quartz.

Chem. Char.—Fusible before the blow-pipe.

Localities, &c.—Compact feldspar is found in Sax- ony, and in the Tyrol. It is not uncommon in Scot- land, as in the Grampian mountains, and on the Penti- land hills in the neighbourhood of Edinburgh. The crystals of feldspar observed in antique green porphyry, are supposed to belong to this variety. Subspecies 5. Hollow Spar, or Chiafolite.

Macle, Broch. ii. 514. Id. Hauy, iii. 267.

Effem. Char.—Divisions parallel to the faces of a prism, slightly rhomboidal. A black substance surrounded by another of a whitish colour.

Exter. Char.—This mineral has been found only crystallized in four-sided, nearly rectangular prisms. The summit is always broken, by which the arrangement of the two substances is observed. The white part is the outermost; the black matter forms in the centre a small prism, whose sides correspond with those of the outer crystal. From the angles of the central prism proceed four narrow lines, which extend to each of the angles of the outer prism; and sometimes this black substance forms at the extremity of these lines, or in the angles of the large prism, a similar small prism of black matter. The black matter is an argillaceous schistus, similar to the repository of the crystals. The white part is sometimes weakly shining; internal lustre glimmering, resinous. The black part is nearly dull. Fracture foliated; the black part earthy.

The colour of the white part, yellowish, or grayish white; that of the black part, grayish, or bluish black. Opaque, or translucent. Semihard; scratching glass when foliated. Streak white. Brittle; not very fragile. Spec. grav. 2.944. Communicates to sealing wax, negative electricity by friction.

Chem. Char.—Before the blow-pipe, the white part melts into a whiter glass; the black part into a black glass.

Localities, &c.—This mineral has been found in Brittany in France, imbedded in argillaceous schistus; in the Pyrenees, in a similar rock, lying immediately on granite, near St Jacques de Compostella in Spain; and in the mountains of Cumberland, also imbedded in argillaceous schistus.

The name chiafolite is derived from the appearance of the section of the crystal, which is supposed to have some resemblance to the Greek letter χ.

56. Species. Scapolite.

Scapolithe, Brochant. ii. 526. Id. Hauy, iv. 393. Rapiolithe, Abilgaard.

Exter. Char.—This mineral has been found massive, but most frequently crystallized in rectangular, four-sided prisms, having the lateral edges truncated. The crystals are small, sometimes acicular, commonly elongated and aggregated. Their surface is longitudinally streaked and glimmering. Internal lustre weakly shining, vitreous or resinous. Fracture foliated.

Colour grayish white; translucent, or rarely transparent. Scratches glass, and is brittle. Spec. grav. 3.68 to 3.70.

Chem. Char.—Froths up before the blow-pipe, and melts into a white enamel.

Localities, &c.—This mineral has been found in the mines of iron ore near Arendal in Norway. The crystals are mixed with mica and calcareous spar.

57. Species. Arctizite.

Wernerite, Hauy, iii. 119. Id. Brochant, ii. 529.

Effem. Char.—Spec. grav. 3.6. Phosphorescent by heat, but not by percussion.

Exter. Char.—This mineral is found massive, or crystallized in four-sided rectangular prisms, terminated by an obtuse four-sided pyramid. The lateral edges are truncated, so that the prism appears to be eight-sided. Crystals small; lustre resplendent, sometimes weakly shining, and pearly or resinous. Fracture foliated. Folia curved in two directions.

Colour between pistachio green and isabella yellow. Translucent. Scratches glass, and strikes fire with steel. The powder thrown on hot coals phosphoresces in the dark.

Chem. Char.—Before the blow-pipe it froths up, and easily melts into an imperfect white, and opaque enamel. Insoluble in nitric acid.

Localities, &c.—This mineral is found in the iron mines of Northo and Ulrica in Sweden, Bouoon near Arendal in Norway, and at Campo Longo in Switzerland.

58. Species. Diaspore.

Id. Brochant, ii. 507. Id. Hauy, iv. 358.

Exter. Char.—This mineral is of a gray colour. Lustre shining, pearly. Fracture foliated, with the folia a little curved; separates into rhomboids, with angles about 130° and 50°; scratches glass. Spec. grav. 3.4-3.2.

Chem. Char.—A fragment of this stone heated for a little in the flame of a candle decrepitates and disperses in all directions; from this property is obtained its name, which signifies to disperse. Heated in a close crucible to prevent the fragments from flying off, they were reduced to white shining particles, somewhat resembling boracic acid.

Constituent Parts. Vauquelin.

Alumina, 80 Oxide of iron, 3 Water, 17

100

Localities, &c.—The repository of this mineral is unknown. It was connected with an argillaceous ochre rock.

This mineral approaches nearly to hydrargillite or wavellite, described above, in its constituent parts; but the proportions and some of the external characters are different.

59. Species. Spodumene.

Id. D'Andrada, Jour. de Phys. an 8. p. 240. Triphane, Hauy, iv. 407. Id. Brochant, ii. 528.

Exter. Char.—This mineral is found in small masses, which present some appearances of crystallization. Lustre shining, pearly. Fracture in the mass radiated, of single single crystals foliated and divisible in three directions, which sometimes afford an oblique angled prism of about 100° and 82°. Crofs fracture dull, rough, and splintery. In larger masses the fracture is radiated. Lustre shining pearly. Scratches glass.

Colour greenish white or leek green. Translucent at the edges. Brittle. Spec. grav. 3.192 to 3.218.

Chem. Char.—Before the blow-pipe it separates at first into small yellowish plates, and then melts into a grayish white transparent glass.

Constituent Parts. Vauquelin.

| Silica | 56.5 | |--------|------| | Alumina| 24 | | Lime | 5 | | Oxide of iron | 5 | | Lofs | 9.5 |

100.0

Localities, &c.—This mineral has been found in the mines of Utoe near Dalero in Sweden. Its repository seems to be a vein, where it is accompanied with quartz and black mica.

The name tripahne has been given to this mineral by Hauy from its peculiar three-fold natural divisions. It received the name spodumene, which signifies covered with ufoes from D'Andrada.

60. Species. MEIONITE.

Id. Hauy, ii. 586. Id. Brochant, ii. 519.

Effem. Char.—Divisible parallel to the faces of a prism with square bases. Easily fusible into a spongy white glass.

Exter. Char.—It is found crystallized in four-sided rectangular prisms whose lateral edges are always truncated. It is terminated by an obtuse four-sided pyramid set on the lateral edges. Sometimes the lateral edges are doubly truncated, thus forming a sixteen-sided prism. The crystals are small, adhering laterally and arranged in rows to the matrix. Lustre shining, vitreous. Longitudinal fracture foliated, and parallel to the four faces of the prism. Crofs fracture slightly conchoidal.

Colour grayish white. Semi-transparent. Scratches glass.

Chem. Char.—Melts very easily before the blow-pipe with considerable intumescence accompanied with a hissing noise.

Localities, &c.—This mineral has only been found on Vesuvius near Mount Somma. The crystals are usually attached to fragments of foliated limestone.

61. Species. SOMMITE.

Nepheline, Hauy, iii. 186. Id. Brochant, ii. 522.

Effem. Char.—Divisible parallel to the sides and bases of a regular six-sided prism. With difficulty scratches glass.

Exter. Char.—This mineral is found disseminated in grains or in small crystals, which are commonly perfect six-sided prisms. The lateral faces are smooth and shining with a vitreous lustre. Longitudinal fracture foliated. Crofs fracture conchoidal and thinning. Colour grayish white. Translucent, rarely femitranparent. The sharp points scratch glass, the others leave only a white trace. Easily frangible. Specific gravity 3.2441.

Chem. Char.—Fusible into a glass by long continued heat. Becomes opaque in nitric acid, hence the name nepheline, signifying cloudy, given to it by Hauy.

Constituent Parts. Vauquelin.

| Silica | 46 | |--------|----| | Alumina| 49 | | Lime | 2 | | Oxide of iron | 1 | | Lofs | 2 |

100

Localities, &c.—This mineral is found lining the cavities of rocks on Mount Somma, from whence its name somnite. It is accompanied with vesuvian and black scoria, all which are supposed by some to be ejected matters from Vesuvius.

62. Species. ICHTHYOPHTHALMITE.

Id. D'Andrada. Ichthyophthalme, Brochant, ii. 552. Apophyllite, Hauy. Id. Brongniart, i. 385.

Exter. Char.—This mineral is found massive, and crystallized in rhomboids which approach nearly to the cube; in thick fixed tables, and in rectangular four-sided tables, with truncated edges. Lustre shining, pearly. Fracture foliated; cleavage single; crofs fracture fine grained uneven, and weakly shining.

Colour yellowish or greenish white; translucent or femitranparent. Scratches glass; not easily frangible. Spec. grav. 2.46.

Chem. Char.—Exposed to the blow-pipe, is with difficulty reduced to a white enamel. In nitric and muriatic acids it forms a jelly.

Constituent Parts. Fourcroy and Vauquelin.

| Silica | 51 | |--------|----| | Lime | 28 | | Potash | 4 | | Water | 17 |

100

Localities, &c.—This mineral is found in the iron mine of Utoe in Sweden, imbedded in a violet-coloured limestone, and accompanied with greenish hornblende and oxide of iron.

IV. ARGILLACEOUS GENUS.

1. Species. NATIVE ALUMINA.

Native Argil, Kirw. i. 175. L'Alumine Pure, Brochant, i. 318.

Exter Char.—This mineral is found in kidney-form masses; it has no lustre; fracture earthy; fragments blunt edged.

Colours snow or yellowish white; opaque; stains a little; tender or friable; adheres a little to the tongue, feels meagre; gives out an earthy smell when breathed on. Spec. grav. 1.305 to 1.66.

Chem. Chem. Char.—Before the blow-pipe is absolutely infusible, but dissolves almost entirely in acids.

Constituent Parts. Fourcroy.

| Substance | Percentage | |-----------------|------------| | Alumina | 45 | | Sulphate of lime| 24 | | Water | 27 | | Lime and silica | 4 |

But according to the analysis of others, it is composed almost entirely of pure alumina, mixed only with a small proportion of lime and silica.

Localities, &c.—It is found at Halle in Saxony, in part of the garden belonging to the college, immediately under the soil; but being only in small quantity, and in the neighbourhood of a large laboratory, has led to the supposition that it is an artificial production. It is said that it has been also found at Magdeburg in Lower Saxony, in Silesia, near Verona, and in England.

2. Species. Porcelain Earth.

Porcelain Clay, Kirw. i. 178. La Terre Porcelaine, Brochant, i. 320. Argile Kaolin, et Feldspath Argilliforme, Haury, ii. 616.

Exter. Char.—This mineral is found massive, or disseminated; has no lustre; stains strongly; has little coherence; adheres a little to the tongue.

Colour reddish, yellowish, or grayish white.

Chem. Char.—Infusible in the strongest heat of a furnace.

Constituent Parts. Vauquelin.

| Substance | Percentage | |-----------------|------------| | Silica | 55 | | Alumina | 27 | | Lime | 2 | | Oxide of iron | .5 | | Water | 14 | | Loos | 1.5 |

Localities, &c.—This mineral is found in considerable abundance in beds and veins, in granite and gneis, especially when the proportion of feldspar is considerable. It abounds in China and Japan, where it is known by the name of kaolin; in Bohemia, Saxony, Denmark, and particularly in many places of France, as at Limoges and Bayonne, and in Cornwall in England. In many cases it seems to be owing to the decomposition of granite.

Uses.—Porcelain earth, as its name imports, is employed either as it is found native, or mixed in certain proportions with other earths, in the manufacture of porcelain. That from Limoges in France is employed without any addition.

3. Species. Common Clay.

This species is divided into five subspecies: 1. loam; 2. pipe clay; 3. potters clay; 4. variegated clay; and, 5. flat clay.

Subspecies 1. Loam.

Exter. Char.—This mineral is found massive and in great abundance; has no lustre; fracture uneven or fine earthy; fragments very blunt-edged; has little coherence; stains.

Colour yellowish-gray, or spotted with yellow and brown, feels somewhat greasy, and adheres strongly to the tongue.

Localities, &c.—Loam is found in great abundance everywhere, and perhaps it ought to be considered as a mixture of different substances, rather than as a simple mineral.

Subspecies 2. Pipe Clay.

Exter. Char.—This variety is found in great masses; has scarcely any lustre; fracture fine earthy, or fine grained uneven; fragments sharp-edged; has some coherence.

Colour grayish or yellowish white; streak shining; feels greasy, adheres strongly to the tongue, and is easily flangible.

Localities, &c.—It is very abundant in most countries, and is usually found in alluvial land.

Subspecies 3. Potters Clay.

Id. Kirw. i. 180. Argile à Potier, Brochant, i. 322.

Exter. Char.—This variety is also found massive, and in great abundance. It is intermediate between solid and friable; has no lustre; fracture fine grained earthy, sometimes coarse grained uneven; fragments blunt-edged.

Colour yellowish, greenish, or grayish white; sometimes reddish or ochre yellow of various shades. It is opaque, stains a little; streak a little shining; very brittle, and easily flangible; is somewhat ductile; adheres a little to the tongue, and feels greasy.

Chem. Char.—Is differently affected by the blowpipe, according to the proportion of the different substances of which it is composed; but in general is difficult of fusion. Effervesces with acids when the proportion of lime is considerable.

Constituent Parts. Vauquelin.

| Substance | Percentage | |-----------------|------------| | Silica | 43.5 | | Alumina | 33.2 | | Lime | 3.5 | | Oxide of iron | 1 | | Water | 18 | | Loos | .8 |

The proportions of silica and lime vary considerably; the silica is very often the predominant ingredient. Kirwan examined a potters clay, in which he found 63 parts of silica.

Localities, &c.—Potters clay is found in great abundance in most countries, and in similar situations with the former. It often forms thick beds in alluvial land, alternating with beds of sand.

Subspecies 4. Variegated Clay.

Exter. Char.—This mineral is found massive. Has an earthy fracture, a shining streak, and is soft or friable.

The colour is white, red, or yellow, and these different colours are sometimes in stripes, veins and spots. Adheres a little to the tongue, and feels somewhat greasy. It is sectile and light.

As this variety of clay forms with water a less tenacious mass than some of the other varieties, it probably contains a greater proportion of siliceous earth.

Localities, &c.—This mineral is found in Upper Lusatia.

Subspecies 5. SLATY CLAY.

Slate Clay, Shale, Kirwan, i. 182. L'Argile Schisteuse, Brochant, i. 327. Argile Schisteuse Impressionée, Hauy, iv. 448.

Exter. Char.—This subspecies is found massive; internally dull, when free from mica; fracture slaty or earthy; fragments in tables.

Colour grayish, yellowish, or blackish, sometimes reddish or brownish; opaque; soft, sectile, and easily frangible. Adheres to the tongue; feels meagre. Sp. grav. 2.6 to 2.68.

Localities, &c.—Usually accompanies coal, so that it abounds in all coal countries. It is sometimes mixed with sand, mica, and iron pyrites. It is known in this country under the name of shale, and in Scotland particularly by that of till, or described under the more general denomination of one of the coal metals. Slaty clay is still farther distinguished by impressions of ferns, reeds, or grasses. When it is of a black colour, it seems to be owing to a greater proportion of coaly matter.

4. Species. CLAY STONE, or INDURATED CLAY.

Indurated Clay, Kirwan, i. 181. L'Argile Endurcie, Brochant, i. 325.

Exter. Char.—Indurated clay is always found massive; it is dull; fracture compact, or fine earthy; but sometimes splintery or even, and also sometimes slaty. Fragments more or less sharp edged, and sometimes in tables.

Colour usually bluish, yellowish, or greenish gray, and sometimes pearl gray, grayish red, whitish, and brownish. These colours are often mixed, and are arranged in spots and stripes. Opaque, soft, rather brittle; easily frangible; adheres slightly to the tongue; feels greasy. Spec. grav. inconsiderable. Gradually falls to pieces in water, or crumbles into powder. Has but little ductility.

Localities, &c.—Indurated clay is very common. It is found in veins, and sometimes in very extensive beds. It constitutes the basis of many porphyries, especially in Saxony, where it is abundant. It is found in many parts of Scotland, as on the Pentland hills in the neighbourhood of Edinburgh.

Stourbridge clay, according to Mr Kirwan, may be included under this variety. It is of a gray colour; does not adhere to the tongue; part is soon diffused in water, and another part falls into powder. Mr Kirwan found it to contain 12.5% of moisture, 12% of a coarse white sand, 30% of a fine brownish sand, and even the remaining or argillaceous part was not entirely freed from sand but by boiling in acids.

5. Species. ADHESIVE SLATE.

Le Schiste à Polir, Brochant, i. 376. Schiste à Polir, Hauy, iv. 449. Polishing Slate, Klaproth, i. 455. Analyt. Eff. Transl.

Exter. Char.—This mineral is found massive; is always internally dull; has a slaty or fine earthy fracture; fragments slaty or in tables.

Colour clear gray, whitish or reddish; opaque or slightly translucent at the edges; gives a shining streak; is sectile, soft, and very easily frangible; adheres strongly to the tongue; feels meagre. Specific gravity 2.68.

Chem. Char.—Immersed in water, adhesive slate absorbs it greedily, air bubbles being rapidly discharged and with noise; but does not become tenacious. When reduced to powder and calcined, it loses about one-fifth of its weight. Exposed to strong heat, it is converted into a dark gray or yellowish and porous flake. (Brochant).

Constituent Parts. Klaproth.

| Silica | 66.5 | 62.5 | |--------|------|------| | Alumina | 1.7 | 1.7 | | Magnesia | 1.5 | 8 | | Lime | 1.25 | 3 | | Oxide of iron | 2.5 | 4 | | Carbon | 22 | 7 | | Water and air | 19 | 22 | | Loss | 2.25 | 1.8 |

Locality, &c.—Adhesive slate forms considerable beds at Menil-Montant near Paris. In these beds millstone already described is found.

6. Species. POLISHING SLATE.

Le Polierschiefer, Brochant, i. 376.

Exter. Char.—This mineral is found massive; internally it is dull. Fracture slaty, but in some directions earthy. Fragments slaty or in tables.

Colour yellowish gray or white; and different colours appear disposed in stripes; is soft; adheres to the tongue; feels meagre, and is rather light.

Localities, &c.—This mineral has been found only, it is said, in Bohemia, near pseudo volcanoes, and it is supposed, that it is nothing more than indurated coal ashes. It approaches so near in the characters that are given of it to the following, that it might be included under the same species, or considered as a variety of it.

7. Species. TRIPOLI.

Id. Kirw. ii. 202. Le Tripoli, Broch. i. 379. Quartz Aluminifère Tripoléen, Hauy, iv. 467.

Exter. Char.—This mineral is found massive; is dull internally; has a coarse earthy fracture, sometimes slaty; fragments blunt edged.

Colour yellowish gray, and sometimes brownish red. Is soft and somewhat friable; meagre to the feel, but does not adhere to the tongue.

Chem. Char.—It is almost infusible before the blowpipe. Argillaceous pipe. It melts with borax without frothing up. It does not form a paste with water.

**Constituent Parts.** Haasfe.

| Silica | 90 | |--------|----| | Alumina | 7 | | Oxide of iron | 3 |

100

**Localities, &c.**—This substance was formerly brought to Europe from Tripoli; hence the name; but it has since been found in many other places, as in Bavaria, Saxony, and Bohemia; in Russia and in England. It is found in the neighbourhood of basalts, sometimes forming veins; at Potchappel it is disposed in beds among the strata of coal, and near those places where strata of coal have been on fire.

**Uses.**—Tripoli is employed in polishing metals, precious stones, and glasses for optical instruments.

8. Species. **FLOATSTONE.**

**Exter. Char.**—This mineral has been found in tubercular porous masses; it is dull, has an earthy fracture, and blunt-edged fragments.

The colour is yellowish gray or grayish white. It is soft and brittle; rough to the feel, and gives out a creaking sound. It is very light, from which it has its name.

**Localities, &c.**—Has been only found at St Omer near Paris.

9. Species. **ALUM STONE.**

**La Pierre Alumineuse,** Broch. i. 381.

**Exter. Char.**—This stone is found massive; it is generally dull; rarely a little glimmering; fracture uneven, sometimes splintery; fragments not very sharp-edged.

Colour grayish or yellowish white; it is soft, and sometimes semifluid; stains a little, and adheres to the tongue.

**Chem. Char.**—This mineral does not effervesce with acids; but after being heated and dissolved in water, it affords alum. According to Bergman it contains 43% of sulphur, 35% of alumina, and 22% of silica; but the following is the result of Vauquelin's analysis.

**Constituent Parts.**

| Alumina | 43.92 | |---------|-------| | Silica | 24 | | Sulphurous acid | 25 | | Sulphate of potash | 3.08 | | Water | 4 |

100.00

**Localities, &c.**—This mineral has been long known under the name of the stone of Tolfa, from the name of the place where it is found near Rome, and where it forms a mountain which is traversed by veins of whitish gray quartz. It is from this stone that the Roman alum, so celebrated in commerce, is manufactured; and it has been supposed that the excellence of the alum is owing to the mineral containing within itself all the ingredients necessary in the formation of that triple salt.

10. Species. **ALUMINOUS SCHISTUS.**

This is divided into two varieties or subspecies; 1. common; and, 2. shining.

**Subspecies 1. COMMON ALUMINOUS SCHISTUS.**

**Le Schiste Alumineux,** Broch. i. 386.

**Exter. Char.**—This mineral is found in masses, which often contain pieces of a globular form. It is sometimes glimmering, and sometimes dull; fracture commonly flat, and sometimes a little earthy; fragments in tables; streak the same as the colour of the mineral, a little shining.

Colour grayish black or brownish; is soft; meagre to the feel, and easily frangible.

**Chem. Char.**—When exposed to the air for some time it separates, and yields alum by lixiviation.

**Localities, &c.**—Aluminous schistus is abundant in Saxony, Bohemia, France, England, and some parts of Scotland. It is disposed in beds among stratiform rocks, and in transition rocks, and it is often traversed by veins of quartz. Being mixed with pyrites, the decomposition is thus promoted when exposed to the air.

**Uses.**—This mineral is dug out for the purpose of extracting alum, first by exposing it to the air or heat, and then by lixiviation.

**Subspecies 2. SHINING ALUMINOUS SCHISTUS.**

**Le Schiste Alumineux Eclatant,** Broch. i. 388.

**Exter. Char.**—This mineral approaches very nearly to the former in most of its characters, but in the direction of its principal fracture the external surface is smooth; lustre shining, or resplendent, resinous, and even somewhat metallic; in the opposite directions it is dull. Fracture commonly flat, and somewhat curved; fragments in tables.

Colour intermediate between bluish and grayish black, and sometimes iron black. Colours in the rents iridescent.

In other characters and circumstances it resembles the former.

11. Species. **BITUMINOUS SCHISTUS.**

**Le Schiste Bitumineux,** Broch. i. 289. Bituminous Shale, Kirw. i. 183.

**Exter. Char.**—This mineral is found massive; lustre glimmering; fracture most commonly thin, rarely thick; fragments in the form of tables, sometimes trapezoidal.

Colour brownish black, sometimes gray, or blackish brown; soft, and easily frangible; adheres slightly to the tongue; streak shining; feels greasy.

**Chem. Char.**—When placed on burning coals it gives out a pale flame with a sulphureous odour, becomes white, and loses a good deal of its weight.

**Localities, &c.**—This mineral is peculiar to coal countries, which it always accompanies, and alternates with 12. Species. Drawing Slate.

Black Chalk, Kirwan, i. 195. Le Schiste à Dessiner, Broch. i. 391. Argile Schisteuse Graphique, Hauy, iv. 447.

Exter. Char.—This mineral is found massive, usually dull; but in the direction of the principal fracture a little glimmering; fracture in certain directions curved flatly; in others fine grained earthly; fragments splintery or tabular.

Colour grayish or bluish black; opaque; stains black; soft; meagre to the feel.

Chem. Char.—Before the blow-pipe it becomes covered with a kind of varnish.

| Constituent Parts | Wiegleb | |------------------|--------| | Silica | 64.50 | | Alumina | 11.25 | | Carbone | 11 | | Oxide of iron | 2.75 | | Water | 7.50 | | Loes | 3 |

Localities, &c.—Drawing slate frequently accompanies aluminous schists. It forms along with it beds which are subordinate to clay slate. It is found in Italy, where it is an object of commerce. It is also found in Spain, France, and some parts of Scotland.

Uses.—As its name indicates, it is employed like black chalk in drawing.

13. Species. Whet Slate.

Novaculite, Kirw. i. 238. Le Schiste à Aiguiser, Brochant, i. 393. Argile Schisteuse Novaculaire, Hauy, iv. 448.

Exter. Char.—This mineral is found massive; is scarcely glimmering; fracture in large masses flatly, in small pieces splintery; fragments tabular.

Colour commonly greenish gray, or smoke gray. Sometimes mountain green; translucent at the edges; semihard, but varying between hard and soft; rather easily frangible; streak grayish white; feels greasy; does not adhere to the tongue. Specific gravity 2.722.

Chem. Char.—Does not effervescence with acids, and is insoluble before the blow-pipe.

Localities, &c.—Whet slate is found in primitive mountains, where it forms beds which are subordinate to clay slate. It was originally brought from the Levant; but has since been discovered in Bohemia, Saxony, in Bayreuth, where it is wrought, and in Siberia. An efflorescence has been observed on the surface, which is found to be sulphate of magnesia; from which it is naturally supposed that the base of that salt forms one of its constituent parts.

Uses.—Whet slate, as its name imports, is cut and polished for the purpose of sharpening knives and other instruments; and, reduced to powder, is employed in polishing steel.

14. Species. Clay Slate.

Argillite, or Argillaceous Schistus, or Slate, Kirwan, i. 234. Le Schiste Argileux, Brochant, i. 395. Argile Schisteuse Léguaire, Hauy, iv. 447.

Exter. Char.—Clay slate is found massive, or disseminated, or in rounded pieces; internally it is a little shining or glimmering; rarely dull; the more the fracture is foliated, the greater is its lustre. Lustre sometimes silky, pearly, or femimetallic. Fracture more or less flatly, sometimes curved and waved, sometimes earthly or splintery; fragments tabular, rarely splintery; sometimes cubic or rhomboidal.

Colour chiefly gray of various shades; but sometimes it is reddish, brownish, or yellowish, or reddish brown. Different colours are so disposed as to appear striped, waved, spotted, or dendritic. It is in general soft; sometimes semihard, feelable, and easily frangible. Gives a grayish white streak; feels greasy. Spec. grav. 2.67 to 2.88.

According to Kirwan, clay slate is composed of silica, alumina, lime, magnesia, and iron, with some bituminous particles.

Localities, &c.—Clay slate belongs equally to the primitive, transition, and stratiform rocks, and frequently forms entire mountains. Primitive clay slate is sometimes mixed with quartz, mica, hornblende, garnets, limestone, pyrites, cinnabar as at Idria; in general it abounds with metallic ores, either in veins or in beds.

Clay slate is very abundant in most countries; it is not unfrequent in many parts of Scotland; but the slate of Kildale, and the contiguous islands on the west coast, has long maintained a decided superiority and preference to all others in this country.

Uses.—Clay slate is in extensive use for covering houses, and then it is known in this country by the single word slate. It is also employed in large plates for writing on, or tracing characters that are afterwards to be effaced.

15. Species. Lepidolite.

Id. Kirwan, i. 208. Id. Hauy, iv. 375. La Lepidolithe, Brochant, i. 399.

Exter. Char.—Lepidolite is found massive, and disseminated in small plates, which might be taken for mica. It is usually glimmering, rarely shining. Lustre femimetallic. Fracture fine grained uneven, rarely foliated. Fragments blunt edged.

Colour lilac blue, grayish and reddish brown; translucent. Semihard; sometimes soft; easily frangible; and feels meagre. Is easily scraped with the knife; but is with difficulty reduced to powder by trituration. The powder rubbed between the fingers has a greasy feel. Spec. grav. 2.816 to 2.854.

Chem. Char.—Froths up under the blow-pipe, and melts into a transparent colourless globule; but with the addition of a little nitre it becomes violet. **Mineralogy**

**Argillaceous genus**

**Constituent Parts**

| | Klaproth | Vauquelin | |----------------|----------|-----------| | Silica | 54.5 | 54 | | Alumina | 38.25 | 20 | | Potash | 4 | 18 | | Fluate of lime| - | 4 | | Oxide of iron and manganese | .75 | 1 | | Water and oils| 2.5 | 3 |

**Localities, &c.—** This mineral was first discovered in the mountain Gradilko near Rosena in Moravia, where it is found in considerable masses included in blocks of granite. It is found also in Sweden. Sometimes it is disseminated in quartz rock.

The name, from λίθος, "a scale," is derived from its scaly structure. Lepidolite was at first taken for fluate of lime or zeolite. A red coloured variety of schorlomite was also supposed to be crystallized lepidolite.

**16. Species. MICA**

*Id. Kirw. i. 21.* *Id. Broch i. 402.* *Id. Hauy, iii. 208.*

**Exter. Char.—** Mica is most commonly disseminated in thin tables, rarely massive or crystallized. The primitive form of its crystals is a rectangular prism, whose bases are rhombs with angles of 120° and 60°; the integrant molecule is the same. The usual forms of its crystals are, a six-sided table with equal angles, sometimes very thick, which produces a six-sided prism, and the want of two of the faces produces the table with four rhomboidal faces; but the most common form of mica is in thin plates or scales of no determinate figure. The lateral faces of the tables are smooth and resplendent; lustre metallic; fracture foliated, sometimes curved or waved, and sometimes radiated; fragments in the form of plates.

Colour usually gray, ash, yellowish, greenish, and blackish gray; in thin plates semitransparent, or even transparent; otherwise, only translucent on the edges; semifluid, very easily flammable; flexible and elastic. Sp. grav. 2.79 to 2.93.

**Physical Char.—** Mica rubbed on Spanish wax communicates to it negative electricity.

**Chem. Char.—** Before the blow-pipe it is with difficulty fusible into a whitish gray or green enamel. Black mica yields a black enamel, which is attracted by the magnet.

**Constituent Parts**

| | Vauquelin | Bergman | Kirwan | |----------------|-----------|---------|--------| | Silica | 50 | 40 | 38 | | Alumina | 35 | 45 | 28 | | Lime | 1.33 | | | | Magnesia | 1.35 | 5 | 20 | | Oxide of iron | 7 | 9 | 14 | | Lows | 5.32 | | |

**Localities, &c.—** Mica is one of the most common minerals, forming one of the constituent parts of granite, gneiss, micaceous schistus, and other primitive rocks, and in some of them sometimes forms particular small veins. Mica also enters into the composition of stratiform rocks, as green stone, basalt, wacken.

Cat gold and cat silver are varieties of mica of a gold or silver colour, which have a considerable lustre, but inferior to that of these metals. It may be easily distinguished by the streak, which in the mica affords a whitish powder without any lustre.

**Uses.—** When mica is obtained in large and thin plates, it is employed as a substitute for glass, and for this purpose it has been used for windows of men of war, as on account of its elasticity it is less subject to be broken from the concussion produced by the firing of cannon.

**17. Species. PINITE**

*Micarelle, Kirw. i. 212.* *La Pinite, Broch. i. 456.*

**Exter. Char.—** This mineral has been usually found crystallized in six-sided prisms, having all the lateral edges truncated, or only three alternating edges, or in four-sided rhomboidal prisms. The surfaces of the crystals smooth and a little glimmering; internally it is dull, sometimes a little shining in the cross fracture; the fracture is fine grained, uneven, or (small conchoidal) fragments blunt-edged.

Colour reddish or blackish brown; opaque; the brown variety is slightly transparent; so soft as to be cut with a knife, when it becomes a bluish black; powder bright gray; adheres a little to the tongue; feels greasy; sp. grav. 2.98.

**Constituent Parts**

| | Klaproth | |----------------|----------| | Alumina | 63.75 | | Silica | 29.50 | | Oxide of iron | 6.75 |

**Localities, &c.—** Pinite is found only near Schneeberg in Saxony, in the mine called Pin; hence its name. It is accompanied by quartz, feldspar and mica, which constitute a small grained granite.

**18. Species. POTSTONE**

*Id. Kirw. i. 155.* *La Pierre Ollaire, Broch. i. 405.* *Talc Ollaire, Hauy, iii. 257.*

**Exter. Char.—** Potstone is found massive; internally it is dull, sometimes glimmering or a little shining, pearly; fracture curved flatly, rarely foliated or waved; fragments blunt edged, in the form of tables or scales.

Colour greenish gray, sometimes reddish or yellowish; opaque, rarely translucent on the edges; soft, flexible, and mild, feels greasy; by being breathed upon it emits the argillaceous smell. Spec. grav. 2.76 to 2.86.

**Chem. Char.—** Infusible before the blow-pipe; some varieties absorb a little water. **Mineralogy**

**Constituent Parts. Wiegleb.**

| Silica | 38.12 | |--------|-------| | Magnesia | 38.54 | | Alumina | 6.66 | | Lime | .41 | | Oxide of iron | 15.02 | | Fluoric acid? | .41 | | Lofs | .84 |

Total: 100.00

**Localities, &c.—Potstone is found at Chiavenna, in the Valteline, from which the specimen above analyzed was obtained; at Como, in Switzerland, hence called Como stone. It is also found in Saxony, Hungary, and on the banks of Loch Fine opposite to Inverary in Scotland. Potstone forms entire beds, and is usually accompanied by serpentine, or it is in nests; it is rarely pure, but mixed with chlorite, talc, asbestos, &c.**

**Uses.—On account of the refractory nature of this stone, it is employed in the construction of furnaces where great heat is required; and as it may be cut or turned on the lathe, it has been formed into utensils for the kitchen, and hence the name potstone.**

**Species. Chlorite.**

*Id. Kirw. i. 147. La Chlorite, Broch. i. 408. Tale Chlorite, Hauy, iii. 257.*

Chlorite is divided into four subspecies: 1. earthy; 2. common; 3. foliated; 4. schistose or slaty.

**Subspecies 1. Earthy Chlorite.**

**Exter. Char.—This mineral is composed of small, scaly, thin, and slightly glimmering particles, cohering together, rarely in the form of powder.**

Colour intermediate between mountain green and dark leek green; sometimes brownish; does not stain; feels greasy, but does not adhere to the tongue; gives an earthy smell by breathing on it.

**Chem. Char.—Melts before the blow-pipe into a gray or black enamel.**

**Constituent Parts. Vauquelin.**

| Silica | 26 | |--------|----| | Alumina | 18.50 | | Magnesia | 8 | | Muriate of soda | 2 | | Oxide of iron | 43 | | Water | 2 | | Lofs | .50 |

Total: 100.00

**Localities, &c.—Earthy chlorite is always found in primitive mountains, forming beds which are subordinate to clay slate. It is found in Saxony, Switzerland, Savoy, and in Scotland.**

**Subspecies 2. Common Chlorite.**

**Exter. Char.—This is found massive and disseminated, or in thin superficial layers on other stones; internal lustre slightly glimmering, resinous; fracture earthy, or foliated; fragments blunt-edged; soft, sometimes semi-hard.**

Colour similar to the former, and sometimes grayish white; is opaque, easily frangible; gives a light green streak without lustre.

**Constituent Parts. Hoepfner.**

| Silica | 41 | |--------|----| | Magnesia | 39 | | Alumina | 6 | | Lime | 1 | | Oxide of iron | 10 | | Lofs | 3 |

Total: 100

**Localities, &c.—Common chlorite is found in the same places with the former, and indeed it is supposed to be earthy chlorite indurated. At Altenberg in Saxony, it is mixed with pyrites of copper and arsenic, and common hornblende.**

**Subspecies 3. Foliated Chlorite.**

**Exter. Char.—This variety is found massive, disseminated, and crystallized in the form of a six-sided table somewhat elongated; several of these tables being united together, frequently form globular, kidney-form, or botryoidal groups. External lustre glimmering or weakly shining; internal shining, resinous, or pearly; fracture foliated; folia curved; cleavage simple; fragments in tables.**

Colour intermediate between leek and dark green; opaque, or translucent at the edges; streak light green; is soft, feebly, easily frangible, and feels a little greasy.

**Constituent Parts. Lampadius.**

| Silica | 35 | |--------|----| | Magnesia | 29.9 | | Alumina | 18 | | Oxide of iron | 9.7 | | Water | 2.7 | | Lofs | 4.7 |

Total: 100.0

**Localities, &c.—This mineral has been only found on St Gothard in Switzerland; it lines the sides of a vein which traverses micaceous schistus. It is accompanied by crystals of green mica, adularia, and quartz. Brochant suggests that foliated chlorite may perhaps be nothing else than a crystallized mica.**

**Subspecies 4. Schistose Chlorite.**

**Exter. Char.—This variety is found massive; internal lustre weakly shining, sometimes shining, resinous; fracture curved flatly, sometimes waved, or a little splintery; fragments tabular.**

Colour green; is soft, feebly, and easily frangible; streak light green; feels a little greasy; gives the earthy smell by breathing.

**Localities, &c.—Slaty chlorite is found in Norway, Sweden, Switzerland, in different parts of Scotland, as on the banks of Loch Lomond, and in the islands of Bute.** Argillaceous genus. Bute and Arran. Sometimes it forms very extensive beds in mountains of clay slate, to which it is subordinate; and it is frequently accompanied by garnets and magnetic iron, crystallized in octahedrons. The name is derived from the Greek word which signifies green.

20. Species. Hornblende.

This is divided into four subspecies; 1. common; 2. basaltic; 3. labradorite; and 4. schistose.

Subspecies 1. Common Hornblende.

Hornblende, Kirw. i. 163. Hornblende Commune, Broch. i. 415. Amphibole, Hauy, iii. 58.

Exter. Char.—Hornblende is found massive or disseminated, and sometimes crystallized. The forms are a four-sided prism, of which the acute opposite lateral edges are strongly truncated; a six-sided prism with four broad and two narrow faces, slightly truncated on the lateral edges; a similar six-sided prism, short, and having the extremities bevelled; an eight-sided prism, having at its extremities, a convex bevelment. Sometimes the crystals are acicular and in groups; internal lustre shining, vitreous, or pearly; fracture foliated, sometimes radiated, and sometimes fibrous; surface of the fracture longitudinally streaked; fragments sharp-edged, sometimes rhomboidal.

Colour deep black, greenish black, or greenish gray; usually opaque. The green varieties translucient at the edges. Soft or semifluid; not easily frangible; streak greenish gray; gives an earthy smell by breathing on it: sp. grav. 3.6 to 3.88.

Chem. Char.—Before the blow-pipe it melts easily into a grayish black glass.

Constituent Parts.

| Silica | Alumina | Lime | Magnesia | Oxide of iron | Lows | |-------|---------|------|----------|--------------|------| | 37 | 22 | 2 | 16 | 23 | 3 |

Localities, &c.—Hornblende is one of the constituent parts of primitive rocks, as in felsite; and it seems also to be an accidental substance, as in gneiss, primitive limestone, porphyries, and micaceous schists. It is found also in masses or entire beds, as in Saxony; and is very common in most countries, as in Norway, Hungary, and Britain.

Uses.—Sometimes employed as a flux for ores of iron.

Subspecies 2. Basaltic Hornblende.

Basaltine, Kirw. i. 219. Horblende Basaltique, Roch. i. 424.

Exter. Char.—This mineral is most frequently found crystallized in equal six-sided prisms, variously modified or with equal sides; having two narrow and four broad; or four narrow and two broad; or three broad and three narrow alternately. The crystals are imbedded, insulated, or grouped. Surface smooth, shining; internal lustre resplendent, in the cross fracture weakly shining, vitreous; fracture foliated; cross fracture small grained, uneven, or conchoidal. Fragments nearly rhomboidal.

Colour velvet-black, and sometimes with a shade of green; opaque; streak grayish white; semifluid; earthy smell by expiration. Spec. grav. 3.22 to 3.33.

Chem. Char.—Before the blow-pipe melts less easily than the preceding, into a black glass.

Constituent Parts. Bergman.

| Silica | Alumina | Lime | Magnesia | Oxide of iron | Lows | |-------|---------|------|----------|--------------|------| | 58 | 27 | 4 | 1 | 9 | 1 |

Localities, &c.—This mineral, as its name imports, is usually found in basalt. It is also met with in wacken, and in the lava of Vesuvius. It is not uncommon in the basaltic rocks of Silcia, Saxony, and Bohemia, as well as in those of this country. As it is less liable to decomposition than the rocks which contain it, detached crystals are frequently found among decayed basalt.

Subspecies 3. Labradorite Hornblende.

La Hornblende du Labrador, Broch. i. 419.

Exter. Char.—This mineral is found massive, disseminated, in rounded pieces, and very rarely crystallized in four-sided rectangular prisms. Internal lustre shining, somewhat metallic; fracture foliated, sometimes curved.

Colour blackish green, or greenish black; sometimes bronze yellow; scarcely translucent at the edges; semifluid; not difficultly frangible; streak greenish. Spec. grav. 3.28.

Localities, &c.—This mineral is found in the island of St Paul on the Labrador coast, but nothing is known of the nature of its repository.

Subspecies 4. Schistose Hornblende.

Id. Kirw. i. 222. La Hornblende Schisteuse, Broch. i. 428.

Exter. Char.—This variety is found massive; internal lustre weakly shining; fracture in masses flatly; in small pieces radiated, sometimes fibrous; fragments in plates.

Colour greenish, or grayish black; opaque; semifluid; streak greenish gray; rather difficultly frangible; breathed on, gives the earthy smell.

Localities, &c.—Schistose hornblende forms extensive beds in primitive mountains, to which it is subordinate. It seems to be common hornblende more or less mixed with quartz. It is found in Bohemia, Norway, Sweden, in the isle of Skye, and other places of Scotland.

21. Species. Basalt.

Figurate Trap, Trap, Whinstone, &c. Kirw. i. 225.—233. Le Basalte, Broch. i. 430. La Lithoïde Prismaticque, Hauy, iv. 474. Exter. Char.—Basalt forms entire mountains, in the neighbourhood of which it is found in rounded pieces, or in large globular masses; internally it is dull; sometimes glimmering from a mixture of hornblende; fracture uneven, sometimes fine splintery or conchoidal; fragments not very sharp-edged. It is most frequently in distinct concretions, which are prismatic or columnar, more or less regular; sometimes also in globular distinct concretions.

Colour grayish or bluish black, sometimes brownish on the surface; opaque; semifluid; brittle, and very difficultly frangible; streak light ash gray; gives a ringing sound under the hammer. Spec. grav. 2.86 to 3.

Chem. Char.—Melts very easily before the blowpipe into an opaque black glass which acts on the magnet.

Physical Char.—Many basalts affect the magnetic needle, reverting the poles when it is brought near them. This is ascribed to the great proportion of iron which enters into their composition.

Localities, &c.—Basalt is not uncommon in every part of the globe, and in many places it is very abundant. It is found in regular columns in several of the Hebrides on the west coast of Scotland, as in Cannay, Eigg, the Schant Isles, but particularly beautiful in Staffa. Pretty regular columns are observed also at Dunbar, and on the south-west side of Arthur's seat near Edinburgh; but the Giant's Causeway and the rocks about Fairhead on the north coast of Ireland, exhibit the finest and most extensive ranges of columnar basalt in the world.

Basalt, besides being in the columnar form, is often disposed in beds and veins; both of which are very common in different places in Scotland, particularly on the western coast, and in the western isles. See Dr Millar's edition of Williams's Mineral Kingdom.

No subject, in geological speculation, has produced more controversial discussion than the origin of basalt; one party asserting that it is the effect of fusion, while another contends that it must have been deposited from an aqueous solution. Our limits preclude us even from barely stating the arguments which have been propounded by naturalists in support of the theories which different parties have embraced. For an account of some of them, see Geology Index; and for the constituent parts of basalt, and some other facts connected with its natural history, see Basalt.

Uses.—Basalt is sometimes employed as a touchstone, as a flux for ores of iron, and in the manufacture of common bottles. It is also employed for millstones. The ancients employed it in sculpture, for it would appear that some of their vases and statues were formed of it.

22. Species. Wacken.

Id. Kirw. i. 223. La Wakke, Broch. i. 434.

Exter. Char.—Wacken is found massive; it is frequently vesicular, and the cavities are often filled with other minerals; internal appearance dull; fracture even or earthy; fragments rather blunt-edged.

Colour grayish green, grayish black, reddish, or brownish; opaque; streak a little shining; soft or fe-

mihard; easily frangible; feels a little greasy. Spec. Argillaceous genus.

Chem. Char.—Fusible like basalt.

Localities, &c.—Wacken belongs to the stratiform rocks. It contains sometimes petrified wood, and the bones of animals. It constitutes beds sometimes in the middle of basalt, but is often in the form of veins, and is the basis of amygdaloid, the cavities of which are filled with green earth, calcareous spar, &c. Wacken is met with in Saxony, Bohemia, Sweden, and many places of Scotland.

23. Species. Phonolite, or Clinkstone.

Id. Daubuifson, Jour. de Phys. ix. 74. La Pierre Sonante, Broch. i. 437. Klingstein and Porphyrschiefer of the Germans.

Exter. Char.—This mineral is always found massive; internal lustre glimmering; fracture flatly, sometimes uneven or conchoidal; fragments sharp-edged; composed of distinct concretions, which are either in the form of tables, or are columnar, and somewhat regularly grouped together.

Colour gray, ash, greenish, or bluish gray; the colours sometimes have a dendritic appearance; opaque, or translucent at the edges; semifluid, or hard; not difficultly frangible; in thin plates it emits a sound when struck with a hammer, and hence its name. Spec. grav. 2.575.

Chem. Char.—Melts before the blowpipe into a colourless glass.

Constituent Parts.

| Klapproth. | Bergman. | |-----------|---------| | Silica, | 57.25 | 58. | | Alumina, | 23.5 | 24.5 | | Lime, | 2.75 | 3.5 | | Oxide of iron, | 3.25 | 4.5 | | Manganese, | .25 | | | Soda, | 8.1 | 6. | | Water, | 3. | 2. | | Lofs, | 1.9 | 1.5 |

100.00 100.0

The stone analyzed above by Bergman, was from Puy in Velay, in France, and is considered by Dolomieu as volcanic. The other by Klapproth, is from Bohemia. Excepting the small proportion of manganese detected in the latter, the coincidence of the two analyses is very striking.

Localities, &c.—Phonolite is not uncommon in many parts of the world. It is met with in Scotland, in the island of Lamlash near Arran; and it constitutes the greater part of Traprain Law in East Lothian; in both places it is columnar.

24. Species. Lava.

Id. Kirw. i. 400. La Lave, Broch. i. 440. La Scoriée, Haug, iv. 497.

Exter. Char.—This mineral is generally of a porous texture, with cavities of different sizes; lustre glimmering. Argillaceous or a little shining, vitreous; fracture imperfectly conchoidal; fragments not very sharp-edged.

Colour blackish gray, perfect black, or brownish black, sometimes greenish, and rarely white; opaque; semihard; brittle; not difficultly frangible; light.

Chem. Char.—Lava is very fusible, and yields a compact black glass.

Constituent Parts. Bergman.

| Silica | 49 | |--------|----| | Alumina | 35 | | Lime | 4 | | Oxide of iron | 12 |

Localities, &c.—Lava being a volcanic product, is only found in the vicinity of volcanoes.

Uses.—Lavas are employed for the purposes of building; their lightness, arising from the numerous cavities, renders them proper for the construction of vaults.

25. Species. Green Earth.

Id. Kirw. i. 196. La Terre Verte, Brochant, i. 445. Talc Chlorite Zographique, Hauy, iii. 257.

Exter. Char.—Green earth is found massive, or disseminated, or in superficial crusts on balls of agate; internally it is dull; fracture earthy; fragments blunt-edged.

Colour celadon green, or blackish green; opaque; soft; feels slightly greasy; adheres a little to the tongue; streaks weakly shining.

Chem. Char.—Before the blow-pipe it becomes black, but is infusible. It is not acted on by acids, and absorbs water.

Constituent Parts. Klaproth.

| Silica | 53 | |--------|----| | Alumina | 12 | | Lime | 2.5 | | Magnesia | 3.5 | | Oxide of iron | 17 | | Water | 12 | | Lofs | 1 |

Localities, &c.—Green earth is found at Verona, where it is wrought, and constitutes an article of commerce; and it is met with in all amygdaloid rocks.

Uses.—Green earth is employed as a colouring matter in painting.

26. Species. Lithomarga.

Id. Kirw. i. 187. La Moelle de Pierre, Brochant, i. 447. Argile Lithomarge, Hauy, iv. 444.

This is divided into two subspecies, chiefly distinguished by their cohesion. These are, 1. friable; 2. indurated.

Subspecies 1. Friable Lithomarga.

Exter. Char.—This is found massive or disseminated; is slightly glimmering; adheres strongly to the tongue; feels greasy.

Colour yellowish white, snow white; sometimes reddish; the particles have very little cohesion.

Subspecies 2. Indurated Lithomarga.

Exter. Char.—This is also found massive or disseminated; is dull; has a fine grained earthy fracture, sometimes conchoidal; blunt-edged.

Colour white, yellowish, or reddish white; brownish red, and several shades of yellow. Different colours are disposed in spots, veins, dots, stripes, or clouds; opaque; very soft; streak shining; adheres to the tongue; feels greasy.

Chem. Char.—Infusible before the blow-pipe; falls to pieces in water without forming a paste. According to some analyses, it contains a large proportion of magnesia.

Physical Char.—Some varieties when rubbed with a feather in the dark, give a little light.

Localities, &c.—Lithomarga or stone marrow, derives its name from its being found in nodules in amygdaloid rocks; it occupies veins or small fissures in porphyry, gneis, and ferpentine. It is found in Bohemia, Saxony, France, England, and at the Giant's caufeway in Ireland. A variety of lithomarga, which exhibits many fine colours, particularly violet or lavender blue, is found in beds reposing on coal at Planitz, near Zwickau in Saxony. It has been called, from its beautiful appearance, wonder earth of Saxony (Terra miraculosa).

27. Species. Mountain or Rock Soap.

Le Savon de Montagne, Brochant, i. 453.

Exter. Char.—This mineral is found massive; is dull internally; has an earthy, and sometimes an imperfectly conchoidal fracture; fragments blunt-edged.

Colour brownish black, spotted ochre yellow. Opaque; very soft; easily frangible; streak shining, and resinous; stains and writes on paper; feels greasy, and adheres strongly to the tongue.

Localities, &c.—This mineral is rare; has been found at Olkutisch in Poland, and also, it is said, in England.

28. Species. Umber.

Exter. Char.—This mineral is found massive; fracture conchoidal; fragments blunt-edged.

Colour brownish, of various shades; soft; adheres a little to the tongue, and has a meagre feel.

Localities, &c.—Umber is found disposed in beds, in the island of Cyprus; and it is employed as a pigment.

29. Species. Yellow Earth.

Id. Kirw. i. 194. La Terre Jaune, Broch. i. 455.

Exter. Char.—Yellow earth is found massive; it is dull, or in the principal fracture, which is flat, glimmering; cross fracture earthy; fragments very blunt-edged.

Colour ochre yellow; very soft; streak shining; feels greasy, and adheres a little to the tongue.

Localities, &c.—It has only been found in small beds in stratified mountains, at Wehraw in Upper Lusatia, V. MAGNESIAN GENUS.

1. Species. NATIVE MAGNESIA.

Magnesia Native, Brochant, ii. 449.

Exter. Char.—Native magnesia is found massive, tuberous or carious. Surface uneven and dull. Fracture flat, conchoidal, splintery or earthy. Fragments sharp-edged.

Colour yellowish gray, with spots and dendritic delineations of black or blackish brown. Opaque, soft and easily frangible. Feels greasy; adheres to the tongue, and is rather light.

Constituent Parts.

| Component | Percentage | |-----------------|------------| | Carbonic acid | 51 | | Magnesia | 47.4 | | A trace of iron | 1.6 | | Lofs | 102.0 |

Localities, &c.—This mineral was discovered by Dr Mitchell in a serpentine rock at Roubischitz in Moravia.

A mineral in many respects similar to this has been analyzed by Giobert*. It was long known under the name porcelain earth, and was successfully employed in that manufacture. Giobert supposes that the external characters, and particularly the colours, of the mineral found in Moravia, seem to indicate the existence of other substances beside those detected by Dr Mitchell's analysis.

Exter. Char.—The mineral described by Giobert is found massive or in mammillary fragments, some of which are tuberculated. Surface dull. Fracture conchoidal or uneven.

Colour pure white. Opaque. Spec. grav. variable. Hard, sometimes soft. Feels greasy; adheres slightly to the tongue. The softer varieties absorb water greedily and with a hissing noise.

Chem. Char.—Insoluble before the blow-pipe.

Constituent Parts.

| Component | Percentage | |-----------------|------------| | Magnesia | 68 | | Carbonic acid | 12 | | Silica | 15.6 | | Sulphate of lime| 1.6 | | Water | 3 | | Lofs | 100.2 |

Localities, &c.—This mineral is found at Baudisfero, in a vein which traverses a steatitic rock of which the mountain is composed.

2. Species. BOLE.

Id. Kirw. i. 190. Le Bol, Broch. i. 459. Argile Ochreuse, Hauy, 445.

Exter. Char.—Found massive and disseminated; surface dull, sometimes a little glimmering; fracture conchoidal; fragments sharp-edged.

Colour yellowish brown or reddish, with spots and dentritical figures of black; opaque, rarely translucent at the edges; very soft; easily frangible; adheres to the tongue; feels greasy; streak shining; sp. grav. 1.4 to 2.

Chem. Char.—Before the blow-pipe it becomes black or gray, and melts into a greenish gray flag. Falls pieces in water with a crackling noise, and without forming a palte.

Constituent Parts, Bergman.

| Component | Percentage | |-----------------|------------| | Silica | 47 | | Alumina | 19 | | Magnesia | 6.2 | | Lime | 5.4 | | Oxide of iron | 5.4 | | Water | 17 | | Lofs | 100.0 |

Localities, &c.—The chief places which yield bole are the island of Lemnos, hence called Lemnian earth; Sienna in Italy, and Strigau in Silea, in which latter place it is deposited on indurated clay; in Upper Lusatia it forms nests in basalt.

Uses.—Bole and similar earths were formerly employed in medicine; it is now only used in the preparation of colours.

CIMOLITE.

This is a mineral which in many of its characters is closely connected with the preceding.

Exter. Char.—It is found massive; fracture earthy uneven, or flat; colour grayish white, pearl gray, and exposed for some time to the air, reddish; opaque; does not stain; adheres strongly to the tongue; is soft, and difficultly frangible; sp. grav. 2.

Chem. Char.—Before the blow-pipe it becomes at first of a deep gray colour, but afterwards white.

Constituent Parts, Klaproth.

| Component | Percentage | |-----------------|------------| | Silica | 63 | | Alumina | 23 | | Oxide of iron | 1.25 | | Water | 12 | | Lofs | .75 | | Lofs | 100.00 |

Localities, &c.—This mineral was brought by Mr Hawkins from the island of Argentiers, formerly Cimolo, from whence it has its name. Olivier found a similar substance in the island of Milo, but which was very friable.

Uses.—This substance is employed in whitening woollen stuffs. It is described by Pliny under the name Cimolia, as being applied to the same purpose, and also as a medicine in his time.

It is to be observed that cimolite contains, according to the above analysis, no magnesia.

3. Species. SEA FROTH.

Keffekill, Kirw. i. 144. L'Ecume de Mer, Broch. i. 462. Argile glaie, Hauy, iv. 443. Meerfschaum of the Germans. Exter. Char.—This mineral is found massive, disseminated, or in superficial layers. Surface dull. Fracture fine earthy, sometimes flatly. Fragments sharp edged.

Colour yellowish white. Opaque. Very soft. Easily frangible. Streak shining. Feels greasy; and adheres to the tongue. Sp. gr. 1.6

Chem. Char.—Infusible before the blow-pipe.

Constituent Parts. Klaproth.

| Silica | 50.5 | |--------|------| | Magnesia | 17.25 | | Lime | .5 | | Water | 25. | | Carbonic acid | 5. | | Lofs | 1.75 |

100.00

Localities, &c.—Sea froth is found in Natolia, in the Crimea, in Spain and some other places. It appears to be distributed in low grounds in thin beds; and it is said to be in the state of soft paste which hardens in the air.

Uses.—It is employed in Turkey, in the manufacture of the heads of tobacco pipes; and as a detergent substance, like fuller's earth, by the Tartars.

4. Species. FULLERS EARTH.

Id. Kirw. i. 184. La Terra à Foulon, Broch. i. 464. Argile Smetique, Hauy, iv. 443.

Exter. Char.—Found massive. Surface dull. Fracture fine-grained earthy, conchoidal or flatly. Fragments blunt-edged.

Colour olive green, yellowish or reddish. Colours sometimes mixed and disposed in spots or stripes; opake; soft or friable. Streak somewhat shining. Sometimes adheres to the tongue; feels greasy.

Chem. Char.—Does not effervescence with acids; melts into a brown spongy clay; falls to pieces in water without forming a paste, and does not froth up like soap.

Constituent Parts. Bergman.

| Silica | 51.8 | |--------|------| | Alumina | 25. | | Lime | 3.3 | | Magnesia | .7 | | Oxide of iron | 3.7 | | Water | 15.5 |

100.00

Localities, &c.—Fullers earth is found in Sweden, Saxony, and France, forming beds; but the best fullers earth is found between strata of sandstone in Hampshire and some other places of England.

Uses.—Fullers earth is of great importance in woollen manufactures, on account of its detergent properties. It is extensively employed in the process of fulling or cleaning woollen stuffs from greasy matters.

5. Species. STEATITES.

La Pierre de Lard, ou Steatite, Broch. i. 474. Semi-indurated and Foliated Steatites, Kirw. i. 151, and 154. Talc Steatite, Hauy, iii. 256.

Exter. Char.—Steatites is found massive, disseminated, and crystallized. Forms of the crystals, a six-sided prism terminated by a six-sided pyramid; a rectangular and rhombohedral four-sided prism; and a double six-sided pyramid. The crystals are finally generally imbedded in the massive variety; but they are very rare; and it is supposed, with some probability, that they are pseudocrystals. Surface of the crystals smooth and shining. Internally dull; fracture coarse splintery, rarely earthy or flatly. Fragments blunt-edged.

Colour greenish, yellowish, reddish or grayish. Colours sometimes mixed, and spotted or dendritical. Translucent at the edges. Soft, sometimes friable. Streak shining. Feels greasy. Sp. gr. 2.614.

Chem. Char.—Infusible before the blow-pipe; but becomes white and very hard.

Constituent Parts. Klaproth.

| From Cornwall | From Bayreuth | |---------------|--------------| | Silica | 48. | | Magnesia | 20.5 | | Alumina | 14. | | Oxide of iron | 1. | | Water | 15.5 | | Lofs | 1. |

100.00

Localities, &c.—Steatites is found in primitive mountains, forming beds and veins in serpentine rocks; sometimes in metallic veins, as in the tin mines near Freyberg. It is also imbedded in wacken, as in the island of Skye, and in veins of serpentine at Portfoy in Scotland. Steatites is also found in Cornwall in England, and in Sweden, Norway, Saxony, and France.

Uses.—Steatites is sometimes employed in the manufacture of porcelain, and some varieties of it answer for the same purpose as fuller's earth.

6. Species. FIGURE STONE.

La Pierre à Sculpture, Broch. i. 451. Le Bildstein of the Germans.

Exter. Char.—This mineral is found massive. Internal lustre sometimes glimmering, sometimes dull, greasy. Fracture flatly; cross fracture splintery.

Colour, olive green, greenish gray, yellowish brown, sometimes reddish, and veined. Semitransparent, or translucent at the edges, and sometimes opake. Soft; felt-like; feels greasy. Sp. gr. 2.78 to 2.81.

Constituent Parts. Klaproth.

| Translucent | Opaque Figure Stone | |-------------|---------------------| | Silica | 54. | | Alumina | 36. | | Lime | — | | Oxide of iron | .75 | | Water | 5.5 | | Lofs | 3.75 |

100.00

Localities, &c.—This mineral is brought from China, and is always cut into various, often singular figures; and hence the name bildstein, or sculpture stone.

7. Species. 7. Species. **Nephrite**, or Jade.

*Jade*, Kirw. i. 171. *Le Nephrite*, Broch. i. 467. *Jade*, Hauy, iv. 368.

This species is divided into two subspecies.

**Subspecies 1. Common Nephrite.**

*Exter. Char.*—This variety is found massive, disseminated, or in rounded pieces. The surface is smooth, glimmering, and unctuous; internally it is dull; fracture flatly or coarse splintery, rarely fibrous; fragments sharp-edged.

Colour leek green, sometimes inclining to blue, greenish or yellowish white; translucent, sometimes only at the edges; hard; very difficultly frangible; feels greasy. Sp. grav. 2.97 to 4.38.

*Chem. Char.*—Fusible before the blow-pipe, and melts into a semitransparent white glass.

**Constituent Parts.** Hoepfner.

| Silica | 47 | |--------|----| | Magnesia | 38 | | Alumina | 4 | | Lime | 2 | | Oxide of iron | 9 |

Localities, &c.—The repository of nephrite is unknown. It was originally brought from the Levant, East Indies, and China. It is found also in the Alps, in Switzerland, and in Piedmont. The water-worn pebbles which are collected on the banks of the lake of Geneva, often contain this mineral. It is found also in a similar form at a particular place on the shores of Iona, one of the Hebrides, in Scotland.

*Uses.*—Oriental nephrite, long known under the name of *Jade*, is held in considerable estimation on account of its hardness and tenacity. It is employed by the Turks for the handles of knives and sabres, and frequently by others for various ornamental purposes.

The property of curing diseases of the kidneys is ascribed to this mineral by ancient authors, and hence the name *nephritic stone*, or *nephrite*.

**Subspecies 2. Axe Stone.**

*La Pierre de hache*, Brochant, i. 470. *Beilstein* of the Germans.

*Exter. Char.*—This is also found massive, but most frequently in rounded pieces; lustre glimmering, or weakly shining; fracture in large masses, flatly; in small, splintery; fragments in the form of plates.

Colour deep meadow-green, sometimes olive green; translucent; semifluid, and sometimes hard; not very brittle; more difficultly frangible than the preceding variety.

Localities, &c.—This mineral is found in China, the East Indies, and South America, on the banks of the river Amazonas. It is found also in some of the islands in the South sea, as well as in Corsica, Switzerland and Saxony.

*Uses.*—Axe stone is employed as hatchets and other cutting instruments by the natives of those countries where iron is little known.

8. Species. **Serpentine.**

*Id.* Kirw. i. 156. *La Serpentine*, Brochant, i. 481. *Roche Serpentineuse*, Hauy, iv. 436.

This species is divided into two subspecies.

**Subspecies 1. Common Serpentine.**

*Exter. Char.*—This mineral is found massive, very rarely disseminated; internal lustre slightly glimmering, or only dull; fracture splintery, or fine-grained uneven, rarely conchoidal; fragments sharp-edged.

Colour blackish green, leek green, grayish, greenish, or bluish grey; in some varieties, red of various shades. These colours are mixed and disposed in spots, stripes, veins, and dots. Translucent at the edges, or opaque; semifluid; not difficultly frangible; feels greasy. Sp. grav. 2.57 to 2.7.

*Chem. Char.*—Fusible before the blow-pipe.

**Constituent Parts.** Kirwan.

| Silica | 45 | |--------|----| | Alumina | 18 | | Magnesia | 22 | | Oxide of iron | 3 | | Water | 12 |

Localities, &c.—Serpentine belongs to the clays of primitive rocks, and it constitutes entire mountains. It is found in Saxony, Bohemia, Italy, Corsica, and Siberia; in Cornwall in England, where it contains native copper, and at Portsoy in the north of Scotland, where it is known by the name of *Portsoy marble*. Common serpentine is frequently mixed with fleecites, talc, albitus, garnets, and magnetic iron, but never contains limestone. This variety, in the language of Werner, is of a newer formation than the following subspecies.

*Uses.*—Serpentine is susceptible of a fine polish; on account of which, and its beautiful colours, it is employed for various ornamental purposes.

**Subspecies 2. Precious Serpentine.**

*Exter. Char.*—This also is found massive or disseminated; internal lustre glimmering, rarely weakly shining, resinous; fracture conchoidal, even or splintery; fragments sharp-edged.

Colour dark leek green of various shades; translucent; semi-hard; easily frangible; feels slightly greasy.

Localities, &c.—This subspecies is found in similar places with the preceding. It is distinguished from it by being always connected with limestone. The stones known in Italy by the name of *verde di Prato*, *verde Antico*, *verde di Susa*, which are very often accompanied by limestone, may be included under precious serpentine.

9. Species. **Schiller Stone.**

*Schillerspath*, or *Spaith Chatoyant*, Brochant, i. 421. *Schiller Spar*, Kirw. 227. **Exter. Char.**—This mineral is found disseminated in thin plates, which assume a crystallized form, as in that of a table with five sides, or a short six-sided prism; lustre shining, sometimes resplendent, and semi-metallic; fracture foliated.

Colour olive green, bronze yellow, or silvery white; soft; easily flangible; somewhat elastic; feels greasy.

**Chem. Char.**—Before the blow-pipe it melts with borax, into a glass which becomes opaque on cooling.

| Constituent Parts | Heyer | |-------------------|-------| | Silica | 52 | | Alumina | 23.33 | | Magnesia | 6 | | Lime | 7 | | Oxide of iron | 11.67 |

Localities, &c.—Schiller stone is found at Bafla in the Hartz, in Moravia, the Tyrol, in Corsica, and in Cornwall. It is usually imbedded in serpentine, and is accompanied by quartz, mica, and copper pyrites. It is supposed by some to be crystallized serpentine.

**10. Species. TALC.**

This species is divided into three subspecies; 1. earthy, 2. common, and 3. indurated talc.

**Subspecies 1. Earthy Talc.**

*Talcite*, Kirw. i. 149. *Le Talc Terreux*, Broch. i. 486.

*Talc Granuleux*, Hauy, iii. 255.

**Exter. Char.**—Earthy talc is found disseminated in kidney-form masses, or in superficial layers; lustre glimmering, pearly; friable; the particles flaky, pulverulent, or slightly cohering.

Colour greenish, reddish, or silvery white; stains; feels greasy, and is light.

Localities, &c.—This mineral is found in Piedmont, Saxony, Bohemia, and in the western parts of Inverness-shire in Scotland, where it exists in veins or cavities of primitive rocks.

**Subspecies 2. Common Talc.**

*Id. or Venetian Talc*, Kirw. i. 150. *Le Talc Commun*, Broch. i. 487. *Talc Laminaire*, Hauy, iii. 255.

**Exter. Char.**—This mineral is found massive, disseminated, and rarely crystallized in very small six-sided tables; lustre shining or resplendent, pearly or metallic; fracture straight or curved foliated; fragments wedge-shaped.

Colour greenish white, pale apple green, reddish or yellowish white; translucent or semitransparent, in thin plates transparent; soft, flexible, but not elastic; feels greasy. Spec. grav. 2.7 to 2.8.

**Chem. Char.**—Insoluble before the blow-pipe, which distinguishes it from chlorite; does not effervescence with acids.

| Constituent Parts | Hoepfner | |-------------------|---------| | Silica | 50 | | Magnesia | 44 | | Alumina | 6 |

Localities, &c.—Common talc is always found in serpentine rocks, where it accompanies actinolite, steatites, and indurated talc. What is called Venetian talc is brought from the mountains of Salzburg and the Tyrol.

Uses.—Talc is sometimes employed as a substitute for chalk, enters into the composition of crayons, and is mixed with some kinds of paint.

**Subspecies 3. Indurated Talc.**

*Le Talc Endurci*, Broch. i. 489.

**Exter. Char.**—This is found massive, and sometimes, it is said, crystallized; lustre shining and resplendent, resinous or pearly; fracture curved foliated, or flat; fragments blunt-edged, tabular.

Colour greenish white, snow white, or apple green; translucent; in thin plates semitransparent; very soft; smooth, and greasy to the feel.

Localities, &c.—Indurated talc forms beds in mountains of argillaceous schistus, gneiss, and serpentine, in the Tyrol, Italy, and Switzerland, and also in the western parts of Scotland.

Uses.—It is applied to the same purposes as the preceding.

**11. Species. ASBESTUS.**

This is divided into four subspecies; 1. mountain cork; 2. amianthus; 3. common asbestos; and, 4. ligniform asbestos.

**Subspecies 1. Mountain Cork.**

*Suber Montanum*, Kirw. i. 163. *Le Liege de Montagne*, Broch. i. 492. *Asbele Treffé*, Hauy, iii. 247.

**Exter. Char.**—This mineral is found massive, often in small plates, which are sometimes thin, and are then denominated mineral paper; sometimes thick, and then called mineral leather; more rarely in porous or cellular pieces, when they are denominated mineral flesh; sometimes it is marked with impressions; the lustre is weakly glimmering or dull; fracture to appearance compact and uneven, but it is fibrous, and the fibres are sometimes parallel, and sometimes interwoven; fragments very blunt-edged.

Colour yellowish or grayish white; opaque; very soft, extremely difficult to break; in thin plates flexible and elastic; creaks when handled; feels meagre. Spec. grav. 0.68 to 0.993.

**Chem. Char.**—Melts before the blow-pipe with difficulty.

| Constituent Parts | Bergman | |-------------------|---------| | Silica | 56.2 | | Magnesia | 26.1 | | Alumina | 2 | | Lime | 12.7 | | Oxide of iron | 3 |

Localities, &c.—This mineral is found in thin veins in serpentine rocks; it is often mixed with quartz, talc, and silver ores, as in Saxony. It is also found in Sweden, Norway, Siberia, Hungary, and in the lead veins at Leadhills in Scotland.

Subspecies Subspecies 2. Amianthus.

Id. Kirw. i. 161. L'Amianthe, Broch. i. 494. Asbeste Flexible, Hauy, iii. 247.

Exter. Char.—This variety is also found massive, more rarely disseminated, and in small detached bundles; lustre glimmering, or a little shining and silky; fracture fibrous straight or parallel.

Colour greenish or silvery white, yellow with white, or greenish gray; opaque; rarely translucent at the edges; very flexible, and even elastic in thin fibres; feels greasy.

Chem. Char.—Melts with difficulty before the blowpipe, into a white, gray, yellow, and sometimes black enamel.

Constituent Parts. Bergman. Chenevix.

| Silica | 64 | 64 | 59 | |--------|----|----|----| | Magnesia | 17.2 | 18.6 | 25 | | Alumina | 2.7 | 3.3 | 3 | | Lime | 13.9 | 6.9 | 9.25 | | Barytes | 6 | | | | Oxide of iron | 2.2 | 1.2 | 2.25 | | Lofs | | | |

Localities, &c.—Amianthus is usually found in primitive rocks, but particularly those of serpentine. It is found in Saxony, Bohemia, Italy, Spain, France, Sweden, and in the western parts of Scotland; but the finest specimens of amianthus are brought from the island of Corsica.

Uses.—On account of the flexibility of this substance it is spun into threads; for this purpose it is mixed with lint, to render the threads less brittle in working them into cloth, which is afterwards passed through the fire that the vegetable matter may be consumed, and the amianthus, which is infusible, remains; and thus an incumbustible cloth is obtained. The ancients manufactured this cloth for the purpose of wrapping round their dead bodies, that their ashes might be preserved unmixed with the wood employed in burning them.

Subspecies 3. Common Asbestus.

Asbeste, Kirw. i. 159. L'Asbeste Commune, Brochant, i. 497. Asbeste Dur, Hauy, iii. 247.

Exter. Char.—This also is found massive; lustre shining and weakly shining, silky or resinous; surface fibrous, the fibres being parallel, straight, or curved; the fibres are more strongly united than in amianthus, and hence sometimes a splintery fracture.

Colour lead green, greenish, or yellowish gray; translucent at the edges; soft, or semifirm; rather easily frangible; little flexible; feels greasy; spec. grav. 2.54 to 2.99.

Chem. Char.—Melts with difficulty before the blowpipe, into a dark gray flag.

Constituent Parts. Wiegleb.

| Silica | 46.66 | |--------|-------| | Magnesia | 48.45 | | Oxide of iron | 4.79 | | Lofs | |

Localities.—It is found in similar situations with the Magnesian preceding, in Saxony, Russia, Sweden, and in the western parts of Scotland.

Subspecies 4. Ligniform Asbestus.

Id. Kirw. i. 161. Le Bois de Montagne, Brochant, i. 499. Asbeste Ligniforme, Hauy, iii. 248.

Exter. Char.—This also is found massive; lustre glimmering, silky; fracture in large masses, curved flatly; in small pieces fibrous, and having the appearance of a woody texture; fragments in elongated plates.

Colour yellowish brown of different shades; opaque; soft; not difficultly frangible; in thin fragments a little flexible, but not elastic; feels meagre; adheres to the tongue; streak shining.

Chem. Char.—Before the blowpipe is only fusible at the edges.

Localities, &c.—This variety is found in the Tyrol, where it is accompanied by galena, black blende, and a grayish white quartz.

12. Species. Cyanite.

Id. Kirw. i. 209. La Cyanite, Broch. i. 501. Sappare, Sauff. § 1900. Difféne, Hauy, iii. 220.

Exter. Char.—This mineral is found massive, disseminated, or crystallized, in four-sided prisms, of which two are broad and two narrow, and having the four lateral edges, or only the two opposite edges, truncated. This prism is often so flattened, as to have the appearance of a table. The broad faces of the crystals are smooth and shining, the narrow faces streaked and only glimmering, almost dull. Internal lustre shining and pearly; fracture curved radiated; that of the crystals foliated; fragments tabular, sometimes splintery, or imperfectly rhomboidal.

Colour blue of various shades, sometimes bluish and pearl gray; and different colours are arranged in stripes, spots, or clouds; translucent, or when crystallized semitransparent, or transparent; semifirm, and sometimes soft; easily frangible; feels greasy. Spec. grav. 3.51 to 3.62.

Chem. Char.—Entirely infusible before the blowpipe, on which account this mineral was employed by Sauffure as a support for other substances in experiments with that instrument.

Constituent Parts. Sauffure.

| Silica | 29.2 | |--------|------| | Alumina | 55 | | Lime | 2.25 | | Magnesia | 2 | | Oxide of iron | 6.65 | | Water and lofs | 4.9 |

Localities, &c.—Cyanite is found on St Gothard in Switzerland, in crystals mixed with quartz, garnets, and granite, and imbedded in indurated talc. It is also found in Spain, France, Carinthia, Bavaria, Siberia, and in the north of Scotland, and always in primitive mountains. 13. Species. ACTYNOLITE.

This is divided into three species; 1. asbestosous, 2. common, and 3. glassy.

Subspecies 1. ASBESTOUS ACTYNOLITE.

Amianthinite, Kirw. i. 164, and Metalliform Afbefloid, ibid. 167. La Rayonnante Afbefforme, Broch. i. 504. Afbefote Aciculaire, Hauy, iii. 75.

Exter. Char.—This mineral is found massive, and rarely crystallized in rhomboidal six-sided prisms, two of which are about $124^\circ 30'$, and four about $17^\circ 45'$; lustre glimmering; internal lustre weakly shining, sometimes thinning, pearly; fracture radiated; fragments wedge-shaped.

Colour olive green, leek green, and asparagus green; translucent, or semitransparent; semifirm, or hard; very brittle, and very easily frangible. Spec. grav. 2.95 to 3.49.

Localities, &c.—This variety is found in similar repositories, and in similar places with the preceding.

14 Species. TREMOLITE.

This is also divided into three subspecies; 1. asbestosous, 2. common, and 3. glassy.

Subspecies 1. ASBESTOUS TREMOLITE.

La Tremolithe Afbefforme, Broch. i. 514. Grammatite, Hauy, iii. 227.

Exter. Char.—Found massive, disseminated, and crystallized; and the crystals are capillary or acicular; lustre weakly shining, silky or pearly; fracture radiated or fibrous; fragments splintery and wedge-shaped.

Colour yellowish white, reddish, greenish, or grayish; opaque; translucent at the edges; very soft; easily frangible.

Subspecies 2. COMMON TREMOLITE.

La Tremolithe Commune, Broch. i. 515.

Exter. Char.—Massive, or crystallized in rhomboidal prisms, with angles of $126^\circ 52' 12''$, and $53^\circ 7' 48''$. The crystals are deeply striated longitudinally; external lustre refulgent; internal shining, pearly; fracture radiated, either parallel, divergent, or promiscuous; surfaces of the fracture longitudinally streaked; fragments splintery.

Colour greenish white, reddish, or yellowish; rarely pearl gray; always translucent; in crystals semitransparent; semifirm; brittle; easily frangible; meagre to the feel.

Subspecies 3. GLASSY TREMOLITE.

La Tremolithe Vitreuse, Broch. i. 516.

Exter. Char.—Massive, or crystallized in long needle or awl-shaped prisms; internal lustre shining, and sometimes refulgent; vitreous or pearly; fracture radiated; cross fracture even, and a little oblique; fragments splintery.

Colour greenish or yellowish white; translucent; crystals sometimes transparent; semifirm; brittle; easily frangible; feels meagre. Spec. grav. 2.92 to 3.2, Hauy.

Chem. Char.—Before the blow-pipe it melts into a porous white flag.

Constituent Parts. Bergman.

| Silica | 64 | |--------|----| | Magnesia | 20 | | Alumina | 2.7 | | Lime | 9.3 | | Oxide of iron | 4 |

100.0

Localities, &c.—It is found in Saxony, Switzerland, Norway, and west side of Inverness-shire in Scotland. Its repository is in primitive mountains, where it is accompanied with ores of lead and iron, as well as with quartz and brown blende.

Subspecies 3. GLASSY ACTYNOLITE.

Id. Kirw. i. 168. La Rayonnante Vitreuse, Broch. i. **MINERALOGY**

### Constituent Parts

| Klappoth | Laugier | |----------|---------| | Silica | 65 | White | Gray Tremolite | | Lime | 18 | | 26.5 | | Magnesia | 10.33 | | 16.5 | | Oxide of iron | .16 | | 25 | | Carbonic acid and water | 6.5 | 23 | 5 | | Lofs | .01 | | 2 |

Total: 100.00

**Physical Char.**—By percussion or friction in the dark, a reddish phosphorescent light appears; and the powder thrown on burning coals yields a greenish light.

**Localities, &c.**—Tremolite is found imbedded in limestone, in primitive mountains. It was first discovered in the valley of Tremola by Pini, and hence its name. It is also found in Hungary, Bohemia, and Carinthia, and in the mountains five miles south of Paisley in Scotland, where it is accompanied with prehnite.

### 15. Species. SMARAGDITE.

*Id.* Saufure Voy. § 1313. *Diallage,* Hauy, iii. 125.

*Id.* Brochant, i. 423. and ii. 506.

**Exter. Char.**—Smaragdite has been found massive and disseminated. Internal lustre shining. Fracture foliated. Cleavage single. Fragments rather sharp edged.

Colour, grays or emerald green. Slightly translucent. Semi-hard or soft. Brittle. Spec. grav. 3.

**Chem. Char.**—Before the blow-pipe melts into a gray or greenish enamel.

### Constituent Parts

| Vauquelin | |-----------| | Silica | 50 | | Alumina | 11 | | Lime | 13 | | Magnesia | 6 | | Oxide of iron | 5.5 | | — chromium | 7.5 | | — copper | 1.5 | | Lofs | 5.5 |

Total: 100.0

**Localities, &c.**—This mineral was found by Saufure in the vicinity of Turin, imbedded in nephrite clouded white and blue. It has also been found near the lake of Geneva among the rounded pebbles, and in Corsica in primitive rocks. In Italy, tables and ornamental pieces of furniture are made of smaragdite; and the Italian marble-cutters call it *verde di Corsica.*

### 16. Species. SAHLITE.

*Id.* D'Andrada, Jour de Phys. An. 8. p. 241. *Mala-colithe,* Hauy, iv. 379. *Id.* Brochant, ii. 518.

**Exter. Char.**—Found massive or crystallized in six-sided prisms, having two opposite lateral edges truncat-

ed. Lustre slightly glimmering, resinous, Fracture fo. Calcaceous rhomboidal. Cleavage threefold. Fragments sometimes rhomboidal.

Colour grayish green or bluish gray. In thin plates translucent. Scarcely scratches glass. Very soft to the touch, from which it has the name malacolite. Spec. grav. 3.2307 to 3.2368.

**Chem. Char.**—Fusible before the blow-pipe into a porous glass.

### Constituent Parts

| Vauquelin | |-----------| | Silica | 53 | | Lime | 20 | | Magnesia | 19 | | Alumina | 3 | | Iron and manganese | 4 | | Lofs | 1 |

Total: 100

**Localities, &c.**—This mineral was discovered by D'Andrada in the silver mines of Sahla in Sweden, and hence it derived its name. It was found by the same naturalist at Bufen in Norway. It appears from the observations of Hauy that faholite and augite are very closely allied, not only in structure and external characters in general, but also in their constituent principles; the only difference in their composition is in the proportions of the lime and magnesia, which are smaller in augite than in faholite; but the proportion of iron in the former is considerably greater than in the latter.

### 17. Species. SCHALSTONE, or TABULAR SPAR.

**Exter. Char.**—This mineral is found massive; lustre shining and pearly; fracture foliated or splintery, and coarse fibrous; consists of separate large-grained pieces implicated in each other; and according to Karsten, are very regular.

Colour milk white, yellowish or reddish white; translucent; semi-hard; brittle.

### Constituent Parts

| Silica | 50 | | Lime | 45 | | Water | 5 |

Total: 100

**Localities, &c.**—This mineral was first noticed by Stutz. It is found in the bannet of Temeswar, and is accompanied by crystallized garnets and calcareous spar.

### VI. CALCAREOUS GENUS.

### 1. Species. AGARIC MINERAL, or Mountain Milk.

*Id.* Kirwan, i. 76. *Id.* Brochant, i. 519. *Chaux Carbonaté Spongieuse,* Hauy, ii. 167.

**Exter. Char.**—This mineral is composed of fine pulverulent particles, slightly united together, and nearly friable.

Colour yellowish white, or snow white; stains strongly. Calcaceous ly; feels meagre; does not adhere to the tongue; nearly floats on water.

Chem. Char.—Effervesces with acids, and is entirely dissolved, so that it is chiefly composed of lime and carbonic acid.

Localities, &c.—This mineral is found in the fissures and cavities of calcareous mountains, and it is supposed that it originates from the destruction of the rocks, the particles of which are carried down to the fissures and cavities by rain water. Abundant in Switzerland.

2. Species. Chalk.

Id. Kirwan, i. 71. La Craie, Brochant, i. 521. Chaux Carbonaté Crayeuse, Hauy, ii. 166.

Exter. Char.—Found massive; has a dull appearance; fracture earthy, and fragments blunt edged.

Colour usually snow or yellowish white, sometimes gray or brown; opaque; stains and writes; very soft, and easily frangible; feels meagre; adheres a little to the tongue. Spec. grav. 2.31 to 2.65.

Chem. Char.—Effervesces with acids; before the blow-pipe is calcined, and converted to quicklime. It is almost entirely composed of lime and carbonic acid, with a mixture of a little oxide of iron and some other substances.

Localities, &c.—Chalk forms peculiar stratiform mountains which contain many petrifications, the matter of which is almost always siliceous. They contain also flints arranged in regular strata. No metallic substances are found in chalk. A great body of chalk traverses France from south to north, extending from Champagne to Calais, and continued to England, in the south of which it forms extensive beds. Chalk is also found in the island of Zealand, in the Baltic, in Poland and many other places.

3. Species. Limestone.

This is divided into four subspecies, which are, 1. compact, 2. foliated, 3. fibrous, and 4. pea stone.

Subspecies 1. Compact Limestone.

This subspecies is again divided into two sections; the first including common compact limestone, and the second roe-stone.

A. Common Compact Limestone.

Id. Kirw. i. 82. Id. Broch. i. 523. Chaux Carbonaté Compacte, &c., Hauy, ii. 164.

Exter. Char.—Found massive; external form frequently figured from the numerous petrifications which it contains; internally dull; rarely glimmering; fracture compact, splintery, uneven or earthy; fragments not very sharp-edged.

Colour usually gray, sometimes reddish or yellowish; different colours exhibit spots, stripes, veins, and dendritical figures; translucent at the edges; semihard; brittle; easily frangible; feels meagre; gives a grayish white streak. Spec. grav. 2.6 to 2.7.

Chem. Char.—Dissolves in acids with effervescence.

The constituents of limestone are carbonate of lime, with variable proportions of other earths, and particularly alumina and silica. The following are the constituent parts of magnesian limestone examined by Mr Tennant.

| Lime | 29.5 | |-----------------------|------| | Magnesia | 20.3 | | Carbonic acid | 47.2 | | Alumina and oxide of iron | .8 | | Loss | 2.2 |

100.0

Localities, &c.—Forms very extensive stratiform mountains, and is usually met with along with coal and flintstone. It is very abundant in Saxony, Bohemia, Sweden, France, Switzerland, and Britain. The magnesian limestone is abundant in Yorkshire and Nottinghamshire.

Uses.—The uses of limestone for the purposes of building, and when reduced to the state of quicklime, to form the basis of mortar, as well as in various arts, are well known.

This variety of limestone, when susceptible of a polish, furnishes marbles; which name, although it be applied to very different stones which are susceptible of a polish, and are fit for sculpture, or ornamental architecture, is frequently applied to limestone of this description.

B. Oolite, or Roe Stone.

Id. Brochant, i. 529. Oviform Limestone, Kirw. i. 91. Chaux Carbonaté Globuliforme, Hauy, ii. 171.

Exter. Char.—This is found massive; internally dull; fracture compact; fragments blunt-edged.

Colour yellowish, smoke gray, hair, or reddish brown; opaque; rarely translucent at the edges; semihard; consists of small globular, distinct concretions: the size of the concretions very various. Spec. grav. 2.4 to 2.5.

Localities, &c.—Roe stone is found in Sweden, Switzerland, Saxony, and in the south of England.

The ketton stone of England, and the celebrated Portland stone, belong to this variety. Of the latter some of the principal public buildings in England and Ireland are constructed.

Uses.—It is employed as a building stone; and when of a fine grain, it is polished and employed as marble.

Subspecies 2. Foliated Limestone.

Of this there are two varieties, granularly foliated, and calcareous spar.

A. Granularly Foliated Limestone.

Pierre Calcaire Grenue, Broeh. i. 531. Chaux Carbonaté Saccharoïde, Hauy, ii. 164.

Exter. Char.—Found only massive; lustre thinning, or strongly glimmering; between pearly and vitreous; fracture straight foliated; fragments rather blunt-edged; in granular, distinct concretions, small or fine grained.

Colour usually snow white, grayish, yellowish, greenish, and rarely reddish white, and sometimes it is spotted, veined, or striped; usually translucent; semihard; feels meagre; brittle, and easily frangible. Spec. grav. 2.7 to 2.8. Chem. Char.—Effervescence with acids, and is almost entirely dissolved. Some varieties, however, from an admixture of other substances, are very slowly acted on by acids.

Localities, &c.—Granularly foliated limestone belongs almost exclusively to the primitive and transition mountains, resting on gneis, micaeous schistus, and clay slate, containing, beside other mineral substances, various metallic ores.

It is found in Italy, Saxony, Bohemia, Sweden, Norway, France, and Britain.

Uses.—This variety of limestone is applied to the same purposes as the former.

Of Marbles.—In the language of the architect and statuary, all stones come under the name of marble which are harder than gypsum, are found in large masses, and are susceptible of a good polish.

On this principle many varieties of limestone, granite also and porphyry, serpentine, and even fine-grained basalts, are denominated marbles. But the word among mineralogists is taken in a more restricted sense, and confined to such varieties of dolomite, twinstone, and compact and granularly foliated limestone, as are capable of receiving a good polish. The most valuable of the calcareous marbles, for hardness, durability and colour, are brought from Italy, the Greek islands, and from Syria. When the ancient Romans were at the height of their civilized luxury, they obtained some varieties of marble from Numidia and other countries, which were very much esteemed.

The sculptors of ancient Greece and modern Europe have always held the white granularly foliated limestone in the highest estimation, both on account of its pure colour, delicate translucence, and granular texture, which make it much easier to work than compact limestone. The species called dolomite is softer, and of a finer grain, so that it is even more manageable under the chisel, and therefore many of the smaller works of the Greek sculptors are of this stone; but Paros and Carrara furnish Europe with the greatest quantity of statuary marble. The Parian marble, which consists almost entirely of carbonate of lime, is the purest, softest, and has some degree of transparency; that of Carrara is often mixed with granular quartz in considerable proportion. The following are the architectural marbles which are held in greatest estimation.

1. The marble called bardiglia, from Carrara, is of a deep blue colour, and seems to be the same with the white statuary marble of that place, with the addition of some colouring matter.

2. That variety of marble called cipolin, is statuary marble traversed by veins of mica.

3. Lunachella marble. This is a compact limestone of a brownish gray colour, containing shells which often retain the original pearly lustre. To this variety belongs the fire marble of Bleyberg in Carinthia, in which the imbedded shells are beautifully iridescent.

4. Florentine marble. This is a grayish, compact, argillaceous limestone, exhibiting designs of a yellowish brown colour, and resembling the ruins of houses; hence it is called ruin marble.

5. The marbles of Syria, Sienna, and Arragon, are of a yellow colour, and are in considerable estimation.

6. Brocatello marble. This is a breccia limestone, composed of fragments of a yellowish red and purple colour, which are cemented by semitransparent, white calcareous spar.

7. The marbles known by the names of verde antiche, verde di Corfù, are composed of limestone, calcareous spar, serpentine, and albitus.

8. The British islands afford many fine marbles, of which that of Tiree is the finest and most beautiful. It has often a delicate flesh coloured ground, spotted with green; but its colours, it is said, are apt to fade. Marbles have also been found in the island of Skye, and in the counties of Ross and Sutherland. For a particular account of these, see Williams's Mineral Kingdom. Marble is not uncommon in different parts of England; and in particular Devonshire and Derbyshire afford varieties which are held in considerable estimation on account of their beauty.

Elastic marble. Some varieties of granular limestone, when cut into thin plates, possess a certain degree of elasticity. The marble in which this property was observed, was in the Borghefe palace at Rome. It was got from an ancient building. Dolomieu supposed that marble acquired this property by being deprived of moisture, and Fleuriot de Bellevue confirmed this opinion, by subjecting certain marbles to heat. He found also a natural elastic marble in Mount St Gotthard.

B. CALCAREOUS SPAR.

Common Spar, Kirw. i. 86. Le Spathe Calcaire, Broch. i. 536. Chaux Carbonatée, Hauy, ii. 127.

Eferv. Char.—Divisible into a rhomboid of $101^\circ 49'$ and $78^\circ 3'$. Soluble with effervescence in nitric acid.

Exter. Char.—Calcareous spar is found massive, or disseminated in various forms, as globular, kidneyform, cellular, and stalactitical; but it is most frequently crystallized. The primitive form of its crystals is an obtuse rhomboid, whose angles are $101^\circ 32' 13''$ and $78^\circ 27' 47''$; integrant molecule the same. The variety of forms of calcareous spar is very great. Werner reduces them to three principal or prevailing forms, and from these he deduces the variations and modifications which take place. His principal forms are, 1. The six-sided pyramid; 2. The six-sided prism; and, 3. The three-sided pyramid. But according to others following the same method, the principal forms are the five following: 1. The six-sided pyramid; 2. The six-sided prism; 3. The six-sided table; 4. The three-sided pyramid; and, 5. The hexahedron, including the rhomboid and cube.

1. The six-sided pyramid is either simple or double.

A. Simple. Simple pyramids are the summits of other pyramids, or of prisms, and they are variously modified in being equal sided, acute, or obtuse, having the angles at the base truncated, or having an obtuse three-sided summit slightly convex.

B. Double; in which two pyramids are obliquely united, and variously modified, by having the angles at the base truncated, or the faces of the summit a little convex.

2. The six-sided prism, is also variously modified, by having at each extremity a six-sided acute summit, or a second obtuse summit of three sides, placed alternately on three edges of the first.

3. A six-sided table, which is either perfect with equal or unequal sides, or rounded, or lenticular.

4. The 4. The three-sided pyramid, which is either simple or double, and is also variously modified.

5. The hexahedron, which includes the rhomboid, and this is either perfect, or has convex faces, or has fix obtuse edges truncated; and the cube, which is somewhat rhomboidal. But for a full account of all the varieties and modifications in the crystallization of calcareous spar, the reader is referred to the treatises of Haüy and Brochant.

The crystals of calcareous spar exhibit also a similarity of arrangement. The simple six-sided pyramids are frequently disposed in a globular, fascicular, or stellated form. The six-sided pyramids are disposed in rows; the six-sided prisms are often disposed like steps of stairs, or are fascicular, or kidney-form; some acute three-sided pyramids of calcareous spar have been found hollow, and in some prisms the centre has been observed of another colour. The surface of the crystals commonly smooth; lustre shining or repellent; internal lustre opalescent or shining, vitreous, and sometimes pearly; fracture foliated; cleavage threefold; fragments always rhomboidal.

Colour usually white, grayish, reddish, greenish, or yellowish white, rarely violet blue, or yellowish brown. Various degrees of transparency; when perfectly transparent, refraction is double. It was in this substance that the property of double refraction was first observed, and hence it was called double spar. This singular property engaged the attention and mathematical skill of Newton, Huygens, Buffon, and more lately the celebrated Haüy. Calcareous spar is semihard, brittle, and easily flangible. Sp. grav. about 2.7.

Chem. Char.—Soluble with effervescence in nitric acid, and reduced by calcination to quicklime.

| Constituent Parts. | |-------------------| | Bergman. | Phillips. | | Lime, | 55 | 55.5 | | Carbonic acid, | 33 | 44 | | Water, | 11 | .5 | | **100** | **100.0** |

Physical Char.—Some varieties of calcareous spar, and particularly those from Derbyshire, give out, when heated, a phosphorescent light.

Localities, &c.—Calcareous spar is very common in all kinds of rocks, in veins and cavities, and particularly in mineral veins, accompanied with quartz, fluor spar, heavy spar, and metallic ore. The finest specimens of rhomboidal spar are brought from Iceland, Derbyshire, the Hartz, as well as Saxony, France, and Spain.

The crystallized sandstones of Fontainebleau are real rhomboidal crystals of calcareous spar, which, during the process of crystallization, have been penetrated with particles of sand.

Subspecies 3. Fibrous Limestone.

Id. Kirw. i. 88. La Pierre Calcaire Fibreuse, ou la Stalactite Calcaire, Broch. i. 549. Chaux Carbonatée Concretionnée, Haüy, ii. 168.

Of this subspecies two varieties have been formed, common fibrous, and calcareous sinter.

A. COMMON FIBROUS LIMESTONE.

Exter. Char.—Found massive; lustre weakly shining and pearly; fracture fibrous, sometimes coarse and delicate, straight or parallel, and sometimes radiated; fragments splintery.

Colour usually grayish, reddish, and yellowish white; generally translucent; rarely semitransparent.

Localities, &c.—This variety is found in veins; and some of it is susceptible of a fine polish, and was known to the ancients under the name of calcareous alabaster, to distinguish it from gypseous alabaster.

Satin spar, a beautiful mineral, which is also susceptible of a fine polish, and has a feebly lustre, from which it derives its name, belongs to this variety. It was first discovered in Cumberland, and is but rarely met with in other places.

B. CALCIAREOUS SINTER.

This variety is usually found stalactitical or tuberose, and also sometimes kidney-shaped, botryoidal, tubular, and coralloidal. Surface usually rough, or drusy, rarely smooth; internal lustre glimmering, sometimes weakly thinning, silky, or pearly; fracture fibrous, which is either straight, icopiform, or stellular; fragments wedge-shaped and splintery.

Colour snow white, grayish green, or yellowish white, and these are sometimes arranged in stripes or veins; translucent, sometimes only at the edges; rarely semitransparent; between semihard and soft; brittle and easily flangible. Sp. grav. 2.728.

Localities, &c.—This mineral seems to be a deposition of calcareous particles, formed by the gradual infiltration of water into the cavities and fissures of limestone mountains. They are either deposited in layers on the floor, or suspended from the roof of those grottoes, and in this latter case they assume a great variety of imitative forms. It is found therefore in the celebrated grottoes of Auxelles, Arcy, and Antiparos, and in the cavities of mineral veins at Leadhills.

The singular mineral substance, known by the name of flox ferril, belongs to this variety. This is found in the cavities of veins of spathofe iron ore, from which it has derived its name. It is of a branched or coralloidal form.

Subspecies 4. PISOLITE or Pea-stone.

Oviform Limestone, var. Kirw. i. 91. La Pierre de Pois, Broch. i. 555. Chaux Carbonatée Globuliforme, Haüy, ii. 171.

Exter. Char.—This mineral is found massive, and in the cavities in which it is formed, the surface is kidney-shaped; internally dull; fracture difficult to determine, but appears even; fragments rather sharp-edged.

Colour white, snow white, grayish, reddish or yellowish white; opaque; rarely translucent at the edges; soft, and brittle.

Localities, &c.—Pisolite is found at Carlsbad in Bohemia, where it has been long known, and where an entire bed was discovered in digging the foundations for a church. Each of the grains of pisolite contains for a nucleus a particle of sand. These have been incrusted with the carbonate of lime held in solution by water, water, and particularly by the warm springs of Carlbad. New concentric layers being deposited, they at last fall to the bottom, and are there united into larger masses by new depositions of the same calcareous matter. Pisolites are also found in Hungary and in Silesia.

4. Species. CALCIAREOUS TUA.

Exter. Char.—This mineral has usually the form of the substance on which the calcareous matter has been deposited, as that of mosses which is most common, grass or leaves; internally dull, or weakly glimmering; fracture uneven or earthy; fragments blunt-edged.

Colour yellowish gray of various shades; opaque, or translucent at the edges; soft, brittle, and easily flangible; light; almost floats on water.

Localities, &c.—This substance is found in all limestone countries, through the strata of which water passes, thus forming springs impregnated with carbonate of lime, which is afterwards deposited on plants or other substances. This mineral, therefore, is found in alluvial land, and the process of its formation is constantly going on.

5. Species. FOAM EARTH.

Silvery Chalk, Kirw. i. 78. L'Ecume de Terre, Broch. i. 557.

Exter. Char.—This mineral is found massive, disseminated, or in feathery particles, which are somewhat friable; internal lustre shining or semimetallic; the foliaceous varieties have a curved foliated fracture; fragments blunt-edged.

Colour yellowish or greenish white, sometimes silvery white; opaque; flimsy; very soft or friable; feels a little greasy or silky.

Chem. Char.—Effervesces and dissolves in acids.

Constituent Parts.

| Substance | Amount | |-----------------|--------| | Lime | 51.5 | | Carbonic acid | 39 | | Silica | 5.7 | | Oxide of iron | 3.2 | | Water | 1 |

100.5

Localities, &c.—This mineral has been found in mountains of stratified limestone at Jena in Saxony, and at Eisleben in Thuringia.

This is considered by some as belonging to the following species, and by others as merely a variety of argillaceous mineral.

6. Species. SLATY SPAR.

Argentine, Kirw. i. 105. Le Spathe Schifflieux, Broch. i. 558. Schiefer Spathe of the Germans. Id. Phillips, Phil. Mag. xiv. 289, and 293.

Exter. Char.—Found massive or disseminated; internal lustre shining, pearly; fracture curved foliated; fragments wedge-shaped, or blunt-edged.

Colour grayish, reddish, or yellowish white; translucent; soft; brittle; feels greasy. Spec. grav. 2.723.

Chem. Char.—Effervesces briskly with acids.

Constituent Parts.

| Substance | Amount | |-----------------|--------| | Carbonate of lime | 93.11 | | Silica | .05 | | Oxide of iron | .8 | | Loss | 1.04 |

100.00

Localities, &c.—This mineral is found in Saxony, in a bed of limestone, where it is accompanied with galena; in Norway; and in Cornwall in England.

7. Species. ARRAGONITE.

Arragon Spar, Kirw. i. 87. L'Arragonite, Broch. i. 576. Id. Hauy, iv. 337.

Exter. Char.—This mineral is always found crystallized in six-sided equiangular prisms, or with two opposite faces broader, to which correspond the two faces of an acute bevelment, which terminates the prism. The edges of the bevelment are also truncated. The crystals are variously grouped, and commonly in the form of a cross; crystals streaked longitudinally; lustre shining or resplendent, vitreous; fracture foliated.

Colour grayish or greenish white; translucent and semitransparent; refraction double; hard, scratches calcareous spar; brittle, and easily flangible. Specific gravity 2.946.

Chem. Char.—Effervesces with acids, and is entirely dissolved. The constituent parts, according to numerous and accurate analyses, are the same as those of calcareous spar; but its superior hardness, diversity of form, and other external characters, have long puzzled chemical philosophers; and it still remains undetermined to what that diversity is owing in this mineral.

Localities, &c.—Arragonite was first found imbedded in foliated and fibrous gypsum, in the province of Arragon in Spain, from which it derives its name. It has been also found in France, the Pyrenees, in Saltzburg, sometimes in an argillaceous schistus, and sometimes in quartz, accompanied by calcareous spar and pyrites.

8. Species. BROWN SPAR.

Sidero-Calcite, Kirw. i. 105. Le Spathe Brunissant, Broch. i. 563. Chaux Carbonatée Ferrifère Perlée, Hauy, ii. 179.

Exter. Char.—Found massive or disseminated, or in kidney-shaped, globular, or carious pieces; very often crystallized. The forms are lenses or rhomboids, which latter have either convex or concave faces; double pyramids composed of two pyramids with three obtuse faces; simple three-sided pyramids, and oblique six-sided pyramids. The surface of the crystals druly, rarely smooth; lustre weakly shining or shining; internal lustre shining, pearly, or vitreous; fracture foliated; fragments rhombohedral.

Colour milk-white, grayish, yellowish, or reddish white; bright or brownish red; translucent at the edges; Calcareous edges; semihard; brittle, easily frangible; streak grayish white. Spec. grav. 2.83.

Chem. Char.—Becomes black and hard before the blow-pipe, and unless reduced to powder, effervesces slowly with acids.

**Constituent Parts. Bergman.**

- Carbonate of lime, 50 - Oxide of iron, 22 - Oxide of manganese, 28

100

Localities, &c.—Brown spar is found in Bohemia, Saxony, France, Sweden, and Britain. It is usually found in metallic veins.

9. Species. DOLOMITE.

Id. Kirw. i. III. Dolomie, Brochant, i. 534. Chaux Carbonatée Aluminifère, Haury, ii. 173.

Exter. Char.—Found massive; fracture appears to be foliated; fragments blunt-edged.

Colour grayish or yellowish white; translucent on the edges; semihard; rather difficultly frangible; feels meagre. Spec. grav. 2.85.

**Constituent Parts. Saussure.**

- Lime, 44.29 - Alumina, 5.86 - Magnesia, 1.4 - Oxide of iron, .74 - Carbonic acid, 46. - Loes, 1.71

100.00

Chem. Char.—Effervesces slowly in nitric acid.

Phys. Char.—Phosphoresces in the dark by the percussion of a hard body.

Localities, &c.—This stone was first observed by Dolomieu, among the ancient monuments of Rome; and afterwards he discovered similar stones in the mountains of the Tyrol, and the Alps. It is found abundantly on St Gothard and other primitive mountains. Dolomieu's attention was first attracted to it by its superior hardness and slow effervescence in acids, and analysis shows that it is different from limestone in its composition.

10. Species. RHOOMB or BITTER-SPAR.

Crystallized Muricalcite, Kirw. i. 92. Le Spath Magnésien, Brochant, i. 560. Chaux Carbonatée Magnésifère, Haury, ii. 187.

Exter. Char.—Found massive or disseminated in rhomboidal pieces, which have a crystallized appearance; lustre thinning or resplendent, and vitreous or pearly; fracture foliated; cleavage threefold; fragments rhomboidal.

Colour grayish white, yellowish or reddish brown; translucent at the edges; semihard; brittle; streak snow-white. Spec. grav. 2.48.

Chem. Char.—Becomes gray or brown before the blow-pipe without splitting or fusion. Effervesces a little with acids.

**Constituent Parts. Klaproth.**

| Carbonate of lime | 52 | 73 | |------------------|----|----| | Magnesia | 45 | 25 | | Oxide of iron and manganese | 3 | 2 |

100 100

Localities, &c.—Found in the Tyrol and Salzburg, and in Sweden. It is always accompanied with asbestos, talc, and tremolite, and imbedded in chlorite schistus, ferpentine, and indurated talc.

II. Species. SWINE STONE.

Id. Kirw. i. 89. La Pierre Puante, Brochant, i. 567. Chaux Carbonatée Félide, Haury, ii. 288.

Exter. Char.—Found massive; internal lustre glimmering or dull; fracture splintery, sometimes earthy or foliated; fragments splintery.

Colour grayish black, or blackish brown; opaque, rarely translucent at the edges; streak grayish white; semihard, sometimes soft; easily frangible. Spec. grav. 2.71.

Phys. Char.—When rubbed with a hard body, it gives out a very fetid odour of rotten eggs.

Chem. Char.—Soluble with effervescence in nitric acid; before the blow-pipe is deprived of its odour, which is supposed to be owing to fulphurated hydrogen.

Localities, &c.—Forms entire beds in stratiform limestone rocks, as in France, Saxony, and Sweden.

12. Species. MARL.

This is divided into two subspecies; 1. earthy; and, 2. indurated.

Subspecies 1. EARTHY MARL.

Id. Kirw. i. 74. La Marne Terreuse, Brochant, i. 569. Argile Calcarifère, Haury, iv. 455.

Exter. Char.—This variety is composed of loose or slightly coherent particles; stains a little; feels meagre and rough; is light; almost swims on water.

Colour yellowish gray, or grayish white.

Localities, &c.—Found in many places of France and Germany, as well as in different places of England and Scotland, forming beds in limestone countries, and often immediately under the soil.

Uses.—It is sometimes employed in the manufacture of pottery, but its principal use is for the purposes of agriculture.

Subspecies 2. INDURATED MARL.

Id. Kirw. i. 95. La Marne Endurcie, Brochant, i. 571.

Exter. Char.—Found massive; dull, or slightly glimmering; fracture earthy, splintery, or flaky; fragments blunt-edged.

Colour yellowish, or smoke gray; opaque; streak grayish white; soft; not very brittle; easily frangible. Spec. grav. 1.6 to 2.8. Chem. Char.—Melts before the blow-pipe into a grayish black flag; effervesces briskly with acids.

Marl is considered as a mixture of carbonate of lime and alumina; and according to the different proportions of these ingredients, it is denominated calcareous marl or clay marl, and sometimes it is known in agriculture by the names of soft and hard marl.

Localities, &c.—Found in Bohemia, Saxony, Sweden, Italy, France, and Britain, in stratiform mountains, sometimes in extensive beds, frequently accompanying limestone, coal, and basalt.

Uses.—It is employed in agriculture for improving the soil, sometimes for building, and sometimes as a limestone. It serves also as a flux for some ores of iron.

13. Species. Bituminous Marl Slate.

Marno-bitumineux, Brochant, i. 574. Chaux Carbonatée Bitumineuse, Hauy, ii. 189.

Exter. Char.—Found massive; surface rough, dull, rarely glimmering; or when divided into curved plates, smooth and shining; fracture flatly; straight or waved; fragments tabular.

Colour grayish or brownish black; opaque; streak shining; soft; easily frangible; feels rather meagre.

Chem. Char.—Effervesces with acids; inflames before the blow-pipe; gives out a bituminous odour, and then melts into a black flag.

Localities, &c.—Found in different places of Thuringia, in mountains of stratiform limestone, forming particular beds, which repose frequently on a species of sandstone. It is frequently mixed with different ores of copper, so that it is sometimes wrought as a copper ore. In this bituminous schilus, petrified fishes and marine plants are frequently found, disposed in regular order, from which some have conjectured that they must have died a violent death; or, according to others, that they have been poisoned by the copper with which it abounds.

14. Species. Apatite.

Phosphorite, Kirw. i. 128. L'Apatite Commune, Brochant, i. 580. Chaux Phosphatée, Hauy, ii. 234.

Exter. Char.—Found almost always crystallized, rarely disseminated. The forms of its crystals are, 1. A regular six-sided prism; 2. The same prism truncated on its lateral edges; 3. Also on its angles and terminal edges; 4. Bevelled on each of the lateral edges; 5. With an obtuse and regular six-sided pyramid, and one or both extremities, the summit being slightly truncated; 6. A three-sided prism with the lateral edges bevelled, and the terminal edges truncated; 7. A six sided table, having its terminal edges strongly, and the lateral edges slightly truncated. Lateral faces of the prisms longitudinally streaked; faces of the pyramid smooth; lustre shining and resplendent; internal lustre shining, between resinous and vitreous. Cross fracture foliated; in other directions fine grained, uneven, or conchoidal. Fragments rather sharp-edged.

Colour green of various shades, blue, sometimes pearl gray, and greenish gray; semitransparent, sometimes transparent, or only translucent; semifluid; is scratched by fluor spar; brittle, and easily frangible. Spec. grav. 2.8 to 3.2.

Chem. Char.—Thrown on hot coals it gives out a calcareous genus. It is almost entirely soluble in nitric acid.

Constituent Parts. Klaproth.

| Lime | 55 | |------|----| | Phosphoric acid | 45 |

100

Phys. Char.—Becomes electric by friction, but not by heat.

Localities, &c.—Apatite is found in different places of Germany, chiefly in tin mines, where it is accompanied by fluor spar, quartz, and metallic ores. It is also found in Cornwall in similar circumstances.

15. Species. Asparagus Stone.

La Pierre d'Asperge, Broch. i. 586. Chaux Phosphatée, Hauy, ii. 234.

Exter. Char.—This mineral has been only found crystallized in equiangular six-sided prisms, terminated by a slightly obtuse six-sided pyramid; lateral edges sometimes truncated; lateral faces longitudinally streaked, the others smooth; external lustre shining or resplendent; internal, resplendent and resinous; fracture foliated, cross fracture imperfectly conchoidal; fragments not very sharp-edged.

Colour asparagus green, greenish white; commonly transparent, often only semitransparent, or even translucent; semifluid. Spec. grav. 3.09.

Chem. Char.—Infusible before the blow-pipe; soluble with effervescence in nitric acid, but thrown on hot coals does not phosphoresce.

Constituent Parts. Vauquelin.

| Lime | 53.32 | |------|-------| | Phosphoric acid | 45.72 | | Loes | .96 |

100.00

Localities, &c.—This stone has been found at Caprera, near Cape de Gata in Spain, and also, it is said, near Arendal in Norway.

16. Species. Phosphorite.

L'Apatite Terreuse, Broch. i. 584. Chaux Phosphatée Terreuse, Hauy, ii. 239.

Exter. Char.—Found massive, and having little coherence; dull; fracture earthy, or fine grained uneven; fragments blunt-edged, sometimes wedge-shaped.

Colour yellowish or grayish white; opaque; semifluid; often fissile; easily frangible; feels meagre. Spec. grav. 2.82.

Chem. Char.—Before the blow-pipe it phosphoresces, and according to some, melts into a white glass, but according to others, infusible. Soluble in acids, and with sulphuric acid gives out white vapours. **Mineralogy**

### Constituent Parts

| Constituent Parts | Pelletier | |------------------|----------| | Lime | 59 | | Silica | 2 | | Phosphoric acid | 34 | | Fluoric acid | 2.5 | | Carbonic acid | 1 | | Muriatic acid | .5 | | Oxide of iron | 1 |

Total: 100.0

**Localities, &c.**—This mineral is found in the north of Scotland, and in the province of Estremadura in Spain, where it forms an entire mountain. It is mixed with quartz; has been long known by the inhabitants of the country for its property of phosphorescing when thrown on hot coals.

### Species. Fluor.

This has been divided into three subspecies: 1. earthy; 2. compact; and, 3. fluor spar.

#### Subspecies 1. Earthy Fluor.

*Sandy or Earthy Fluor*, Kirw. i. 126. *Le Fluor Terreux*, Broch. i. 593. *Chaux Flualée Amorphe*, Hauy, ii. 260.

**Exter. Char.**—Is composed of particles which are slightly cohering; dull, or scarcely glimmering.

Colour greenish white, sometimes bluish green; stains a little; feels rough.

**Chem. Char.**—Thrown on hot coals, it gives out a bluish green light.

**Localities, &c.**—Has been found in Hungary, in a vein accompanied with quartz.

#### Subspecies 2. Compact Fluor.

*Id. Kirw. 127.* *Id. Broch. i. 594.*

**Exter. Char.**—Is found massive; dull, lustre sometimes glimmering, vitreous; fracture even, conchoïdal, and rarely splintery; fragments sharp-edged.

Colour greenish gray, or greenish white; sometimes different colours are difposed in spots; translucent; streak shining; hard, and brittle.

**Chem. Char.**—Phosphoresces on hot coals.

**Localities, &c.**—This mineral is found in the Hartz, in Sweden, and Siberia, always accompanying fluor spar.

#### Subspecies 3. Fluor Spar.

*Foliated or Sparry Fluor*, Kirw. i. 127. *Le Spath Fluor*, Broch. i. 595. *Chaux Flualée*, Hauy, ii. 247.

**Effen. Char.**—Insoluble in water, and divisible into a regular octahedron.

**Exter. Char.**—Fluor spar is found massive or diseminated, but most frequently crystallized. Primitive form a regular octahedron, which is easily obtained by mechanical division; integrant molecule a regular tetrahedron. The usual forms are, 1. The cube, which is either perfect, or with truncated edges or truncated angles, or with the edges bevelled, having on each of its angles a three-sided pyramid, corresponding to the faces of the cube. 2. The octahedron, which is either perfect, or has it angles or its edges, or both, truncated. Surface of the crystals smooth, shining or resplendent, sometimes drusy; internal lustre shining, resplendent, and vitreous or pearly; fracture foliated, straight or curved; cleavage fourfold, in the direction of the faces of the regular octahedron; fragments tetrahedral, or rhomboidal.

Colours of fluor spar extremely various and beautiful. The principal are, greenish white, grayish, or yellowish; blue, green, brown, and red, of various shades; and different colours are sometimes arranged in stripes and spots. Most commonly translucent, sometimes transparent, or only translucent at the edges. Semi-hard; brittle; easily frangible. Spec. grav. 3.09 to 3.19.

**Chem. Char.**—Fusible before the blow-pipe into a transparent glass; decrepitates when heated. The powder thrown on hot coals gives out a bluish or greenish phosphorescent light; and two pieces rubbed against each other, shine in the dark.

### Constituent Parts

| Constituent Parts | Scheele | |------------------|--------| | Lime | 57 | | Fluoric acid | 16 | | Water | 27 |

Total: 100

**Localities, &c.**—Fluor spar is sometimes found in beds, but most frequently in mineral veins. It is very common in many places of the world, particularly in Cornwall and Derbyshire, and also in the counties of Durham and Cumberland in England; at Chamouni in Savoy, the octahedral variety of a rose red colour is found. Fluor spar is found also in the interior part of Aberdeenshire in Scotland.

**Uses.**—This mineral is successfully employed as a flux for different metallic ores. As it is susceptible of a fine polish, it is cut and formed into a great variety of ornamental objects, as pyramids, vases, &c., which, on account of the beauty of the colours, are greatly esteemed.

### Species. Gypsum.

This species is divided into four subspecies: 1. earthy; 2. compact; 3. foliated; and, 4. fibrous.

#### Subspecies 1. Earthy Gypsum.

*Farinaceous Gypsum*, Kirw. i. 120. *Le Gypse Terreux*, Broch. i. 601. *Chaux Sulphatée Terreuse*, Hauy, ii. 278.

**Exter. Char.**—This is composed of particles which are more or less cohering; dull, in some places weakly glimmering; feels meagre and rough.

Colour white, gray, or yellowish.

**Localities, &c.**—This substance is rare; it is only found in the fissures and cavities of gypsum rocks, and is supposed to be a deposition of loose particles of gypsum, carried along by water. Found in Saxony, and Mont Martre near Paris. Subspecies 2. Compact Gypsum.

*Id.* Kirw. i. 121. *Id.* Broch. i. 602. *Id.* Hauy, ii. 278.

**Exter. Char.**—Found massive; lustre weakly glimmering, almost dull; fracture compact, even, or splintery; fragments blunt edged.

Colour yellowish and grayish white, sometimes reddish; and different colours exhibit stripes; translucent at the edges; soft, and easily frangible. Spec. grav. about 2.3.

**Localities, &c.**—Found in Italy, Germany, France, Spain, and England.

Subspecies 3. Foliated Gypsum.

Granularly Foliated Gypsum, Kirw. i. 123. *Id.* Broch. i. 606.

**Exter. Char.**—Found massive or disseminated, and sometimes, it is said, crystallized in fix-fided prisms, obtusely bevelled at each extremity; lustre glimmering or shining, between vitreous and pearly; fracture foliated, sometimes radiated; fragments blunt-edged.

Colour usually snow white, grayish, yellowish, or reddish white; and several colours are arranged in spots, stripes, and veins. Translucent, rarely femitransparent; refraction double; very soft; easily frangible. Spec. grav. 2.27 to 2.31.

Foliated gypsum has some resemblance to granular limestone, but may be readily distinguished from it by its softness.

Subspecies 4. Fibrous Gypsum.

*Id.* Kirw i. 122. *Id.* Broch. i. 604. *Id.* Hauy, ii. 278.

**Exter. Char.**—This is found massive, but in thin layers; lustre shining, or weakly shining, pearly; fracture fibrous; in some varieties the longitudinal fracture is foliated; cross fracture fibrous; fragments long, splintery.

Colour snow white, grayish, yellowish, or reddish white; translucent; very soft; easily frangible.

**Chem. Char.**—The different varieties of gypsum possess nearly the same chemical characters. When pure, there is no effervescence with acids. Before the blowpipe gypsum immediately becomes white, is converted into a white enamel, which, at the end of 24 hours, falls into powder.

**Localities, &c.**—Gypsum, in general, constitutes mountains or beds, which are subordinate to sandstone, or limestone. It is found in all kinds of rocks. Gypsum is found in great abundance in the neighbourhood of Paris, in several parts of England, but sparingly in Scotland.

**Ufer.**—Gypsum is employed along with lime as a cement. It is also very extensively employed under the name of plaster of Paris, for making casts and models. With this view it is exposed to a strong heat, to drive off the water of crystallization. It is then in the state of powder, which being again mixed with water, is put into the mould in the form of paste; and, from its strong affinity for water, it soon becomes solid.

19. Species. Selenite.

Broad Foliated Gypsum, Kirw. i. 123. *La Selenite*, Broch. i. 609. *Chaux Sulfatée*, Hauy, ii. 266.

**Exter. Char.**—Divisible into smooth plates, which break under angles of 113° and 67°.

**Exter. Char.**—Selenite is found massive; and frequently also crystallized. The primitive form of its crystals is a four-sided prism, whose bases are obliquely parallelograms; the integrant molecule is the same. The usual forms are, a fix-fided prism, having two broad and two narrow faces, and terminated by an oblique bevelment, whose sides correspond to the broad sides of the prism; a similar prism terminated by a four-sided pyramid; double crystals composed of two of the former united by their smaller lateral faces, so that the summits united form on one side a salient angle, and on the other a re-entering angle; another form is a spheroidal or conic lens. These crystals are often grouped, divergent, fascicular, or stellated; and of the fix sides of the prism, the two opposite are smooth, and the four others longitudinally streaked; lustre repleendent or shining, between vitreous and pearly; fracture foliated, straight or curved; cleavage threefold; fragments rhomboidal, with two faces smooth and shining, and two others streaked.

Colour usually white, grayish, yellowish, or snow white, sometimes iridescent; transparent, sometimes only translucent; very soft; in thin plates, flexible, but not elastic; easily frangible. Spec. grav. 2.32.

**Chem. Char.**—Before the blow pipe more easily fusible than gypsum, and splits into thin plates.

| Constituent Parts | Bergman | |------------------|---------| | Lime | 32 | | Sulphuric acid | 46 | | Water | 22 |

**Localities, &c.**—Selenite is found among beds of gypsum, and particularly among those which alternate with clay and sandstone. It is also found in neffs in clay. It is not uncommon in many places, as among the gypsum rocks near Paris, in different parts of England, and at Lord Glasgow's coal works in Scotland, where it is found among clay, and in the cavities or on the surface of the limestone which repose on the strata of coal.

**Ufer.**—Selenite also, after calcination, is employed in modelling; but it is said that it possesses less solidity than what is obtained from gypsum.

20. Species. Anhydrite.

*Chaux Sulfatée Anhydre*, Hauy, iv. 348.

**Exter. Char.**—This mineral is found massive; lustre shining or weakly shining, and pearly; fracture curved foliated, sometimes radiated, and fine splintery; fragments sharp edged; translucent; semihard; not very brittle, rather easily frangible. Spec. grav. 2.964.

**Chem. Char.**—Before the blow-pipe it neither exfoliates nor becomes white, like selenite. **MINERALOGY**

### Localities, &c.—Found near Arendal in Norway, and some specimens are accompanied by greenish-coloured, foliated talc.

#### VII. BARYTIC GENUS.

1. Species. **Witherite**, or Carbonate of Barytes.

*Barolite*, or Aerated Barytes, Kirw. i. 134. *La Witherite*, Brochant, i. 613. *Baryte Carbonatée*, Hady, ii. 308.

**Effus. Char.**—Forming a white precipitate in weak nitric acid before solution.

**Exter. Char.**—Found massive, or disseminated, rarely crystallized; forms of its crystals are, a six-sided prism, with a six-sided pyramid set on the lateral faces; the same prism having all the angles truncated; a double six-sided pyramid. The crystals, which are small, are usually imbedded in the mineral itself; sometimes grouped in bundles, or crossing each other. Surface smooth; lustre of the principal fracture shining, or weakly shining, resinous; fracture between radiated and foliated; cleavage fracture fine grained uneven; fragments wedge-shaped.

Colour yellowish gray, grayish, or yellowish white; translucent, or semitransparent; semifluid, or soft; brittle; easily flangible. Spec. grav. 4.3 to 4.33.

**Chem. Char.**—Infusible according to Hauy, before the blow-pipe; but according to Brochant, melts before the blow-pipe to a white enamel.

---

### 21. Species. **CUBE SPAR.**

*Chaux Sulfate Anhydride*, Hauy, iv. 348. *Saude Muriate Gypseuse*, Id. ii. 365. *Muriacite*, Klaproth.

**Exter. Char.**—This mineral is found massive, and also crystallized, in four-sided prisms, which are nearly cubical; two of the opposite lateral faces are broader than the other two. The lateral edges are sometimes truncated, and hence arises an eight-sided prism; sometimes also the truncations are so great as to destroy the narrow lateral faces, and form again a six-sided prism. External lustre of the broad faces resplendent and pearly; of the narrow, shining. Internal lustre shining and pearly; fracture foliated; cleavage threefold; fragments cubical.

Colour milk-white, grayish, yellowish, and reddish white; sometimes pearl gray; translucent; semifluid. Spec. grav. 2.92 to 2.96.

---

### 22. Species. **DATHOLITE.**

*Chaux Datholite*, Brochant, ii. 397. *Chaux Borate Silicose*, Haüy.

**Exter. Char.**—This mineral has only been found crystallized; the primitive form is a rectangular prism, with rhombohedral bases, whose angles are 109° 18' and 70° 42'; lustre shining, vitreous; fragments conchoidal.

Colour grayish or greenish white; translucent; scratches fluor spar. Spec. grav. 2.98.

**Chem. Char.**—In the flame of a candle it becomes dull white, and is easily reduced to powder. Before the blow-pipe it melts into a glass of a pale rose-red colour.

---

### Constituent Parts

| Constituent Parts | Klaproth | |-------------------|---------| | Lime | 35.5 | | Silica | 36.5 | | Boracic acid | 24. | | Water | 4. |

100.0

---

### Localities, &c.—Found in the salt pits at Halle in the Tyrol, where it is called splintery gypsum.

---

### 23. Species. **HEAVY SPAR**, or **Sulphate of Barytes.**

This species has been divided into eight subspecies; earthy, compact, granular, foliated, common, columnar, prismatic, and bolognian.

#### Subspecies 1. **Earthy Heavy Spar.**

*Earthy Barofelinite*, Kirwan, i. 138. *Le Spathe Pesant Terreux*, Brochant, i. 617.

Enter. **Part I.**

**Mineralogy.**

**Exter. Char.**—Found massive; lustre scarcely glimmering, or dull; consists of earthy particles, which are slightly cohering; stains a little; feels meagre.

Colour snow white, grayish, yellowish, or reddish white.

**Localities, &c.**—This a rare mineral. It has been found in Saxony, covering masses of heavy spar, and also in Derbyshire and Staffordshire in England.

**Subspecies 2. Compact Heavy Spar.**

**Compact Baroferlenite**, Kirw. i. 138. **Baryte Sulfate**

**Compacte**, Hauy, ii. 303. *Id.* Broch. i. 618.

**Exter. Char.**—Found massive, sometimes in kidney-form or globular pieces, with cubical imprellions; lustre glimmering, sometimes dull, and sometimes weakly shining; fracture coarse earthy, sometimes uneven; fragments not very sharp-edged.

Colour yellowish, grayish white, sometimes pale flesh red; opaque, or translucent at the edges; soft; not very brittle; easily frangible; feels meagre.

**Localities, &c.**—Found in mineral veins in Saxony, and in England; in clay slate, in Savoy; and we have found it in sandstone in Northumberland.

**Subspecies 3. Granular Heavy Spar.**

**Exter. Char.**—This also is found massive; lustre glimmering, nearly shining, and pearly; fracture foliated, or splintery; fragments blunt-edged.

Colour snow-white, milk-white, yellowish, or reddish; translucent; soft; not very brittle; easily frangible. Spec. grav. 3.8.

**Constituent Parts.** Klaproth.

| Constituent Parts | Withering | Bergman | |-------------------|-----------|---------| | Barytes | 67.2 | 84 | | Sulphuric acid | 32.8 | 13 | | Water | - | 3 |

**Localities, &c.**—Found in mineral veins in Saxony, along with galena, and in Siberia, accompanied by copper and silver ores.

**Subspecies 4. Foliated Heavy Spar.**

**Exter. Char.**—Found massive, and in kidney-shaped, globular, and cellular pieces, composed of four-sided tables, or lenes, with a drusy surface; lustre glimmering or shining, between pearly and vitreous; fracture curved foliated, sometimes splintery; fragments not very sharp-edged, sometimes wedge-shaped.

Colour yellowish, reddish, or grayish white, sometimes flesh or brownish red; translucent; soft; not very brittle; easily frangible.

**Localities, &c.**—Is not uncommon in mineral veins; sometimes also in beds, in many countries. It is also found in Britain.

**Subspecies 5. Common Heavy Spar.**

**Foliated Baroferlenite**, Kirw. i. 140. *Broch.* i. 624.

**Exter. Char.**—This mineral is found in masses, or disseminated, and very often crystallized. Its principal forms are, 1. A double four-sided pyramid; 2. A four-sided prism, rectangular or oblique; 3. A four-sided table, rectangular or oblique; 4. A six-sided prism; 5. A six-sided table; and, 6. A long eight-sided table. These forms are variously modified by truncations and bevelments, and they are differently grouped together; the prisms cross one another; the tables are attached by their lateral faces, and form globular or kidney-shaped groups; surfaces smooth, sometimes rough and drusy. Lustre refulgent, shining, glimmering, or only dull; internal lustre shining or refulgent, between pearly and resinous; fracture straight foliated; cleavage threefold; fragments somewhat rhomboidal.

Colour commonly white, snow-white, milk-white, grayish, yellowish, or reddish; in masses translucent; in crystals transparent or semitransparent; refraction double; soft; brittle. Spec. grav. 4.29 to 4.47, and 4.5.

**Chem. Char.**—Fusible before the blow-pipe into a solid white enamel, which being moistened, gives out the odour of sulphurated hydrogen. Does not effervesce with acids.

**Constituent Parts.**

| Constituent Parts | Withering | Bergman | |-------------------|-----------|---------| | Barytes | 67.2 | 84 | | Sulphuric acid | 32.8 | 13 | | Water | - | 3 |

**Localities, &c.**—This is a very common mineral, and particularly in metallic veins that traverse primitive mountains. It accompanies ores of silver, copper, lead, and cobalt, as well as fluor spar, calcareous spar, and quartz.

**Subspecies 6. Columnar Heavy Spar.**

**Le Spoth Pefant en Barres**, Broch. i. 631. **Baryte Sulphatée Bacillaire**, Hauy, ii. 302.

**Exter. Char.**—Found always crystallized: 1. In oblique four-sided prisms; 2. The same prism terminated by an acute bevelment; 3. The same prism terminated by a four-sided pyramid placed on the lateral edges; and, 4. A six-sided prism bevelled at the extremity. The crystals are acicular, and are grouped together in bunches; surface shining; or weakly shining; internal lustre shining; longitudinal fracture radiated; cross fracture even. Fragments rhomboidal.

Colour filvery, grayish, or greenish white; translucent; soft, and brittle.

**Localities, &c.**—Found in Saxony, and Derbyshire in England, accompanied by other varieties of heavy spar, quartz, and fluor spar.

**Subspecies 7. Prismatic Heavy Spar.**

**Exter. Char.**—Found massive, and frequently crystallized. The usual forms are, 1. An oblique four-sided prism, bevelled at the extremities; 2. An oblique four-sided prism, terminated by a four-sided pyramid placed on the lateral edges; 3. An elongated octahedron; and, 4. A six-sided prism. Lustre shining or refulgent, between resinous and pearly; fracture foliated; cleavage threefold. Strontian genus. Colour yellowish, greenish, or pearl gray, sometimes pale blue, and rarely flesh red; translucent; when crystallized, transparent; soft, and not very brittle; very easily frangible.

Localities, &c.—Sometimes found in mineral veins, as in Saxony.

Subspecies 8. BOLOGNIAN HEAVY SPAR.

Le Spath de Bologne, Brochant, i. 633. Striated or fibrous heavy spar, Kirwan, i. 141. Baryte fulgâte radiée, Hauy, ii. 302.

Exter. Char.—This is found in rounded pieces; external surface uneven, dull, or glimmering; internal lustre shining, or weakly shining, between adamantine and pearly; fracture radiated, parallel, diverging, or fibrous, sometimes foliated; fragments splintery, sometimes rhomboidal.

Colour, smoke or yellowish gray; translucent, soft, very brittle, and easily frangible.

Chem. Char.—This mineral has been long known by its property of shining in the dark, after being heated. Other heavy spars, indeed, have a similar property.

Constituent Parts. Arvidson.

| Sulphate of barytes | 62 | | Silica | 15 | | Alumina | 14.75 | | Gypsum | 6 | | Oxide of iron | .25 | | Water | 2 |

100.00

Localities, &c.—This mineral is found at Monte Paterno near Bologna in Italy, in rounded masses, which have an uneven surface; they are imbedded in an argillaceous or marly rock, which is a kind of amygdaloid, and from which they are detached by the action of the waters.

VIII. STRONTIAN GENUS.

1. Species. STRONTITES, Carbonate.

La Strontianite, Brochant, i. 637. Id. Kirw. i. 332. Strontiane Carbonatée, Hauy, ii. 327.

Effem. Char.—Soluble in nitric acid with effervescence; paper dipped in the solution, and dried, burns with a purple flame.

Exter. Char.—Found massive, and sometimes crystallized in needles, which are grouped together; form of the crystals a regular six-sided prism; lustre weakly shining, or only glimmering; internal lustre shining, and weakly shining, between refrinous and pearly; fracture radiated, straight, diverging, or fibrous; cros fracture fine grained, uneven, or splintery; fragments wedge-shaped, or sharp-edged.

Colour asparagus green, greenish, whitish, or yellowish gray; translucent; semifluid, brittle and easily frangible; feels a little greasy. Spec. grav. 3.4 to 3.67.

Chem. Char.—Before the blow-pipe whitens without fusion, and afterwards exposed to the air, falls to powder.

Constituent Parts. Klaproth.

| Strontites | 69.5 | | Carbonic acid | 30 | | Water | .5 |

100.00

Localities, &c.—This mineral has been hitherto found only at Strontian in Scotland, in a lead vein which traverses a gneiss rock. It is said also to have been found at Leadhills.

2. Species. CELESTINE, Sulphate of Strontites.

La Celestine, Brochant, i. 640. Strontiane sulfatée, Hauy, ii. 313.

Effem. Char.—Divisible into a rhomboidal prism, with angles of about 105° and 75°; gives a light red colour to the blue part of the flame produced by the blow-pipe.

Exter. Char.—Primitive form of its crystals a rectangular prism, whose bases are rhombs; integrant molecule a triangular prism with square bases. The forms under which it generally appears are four or six-sided prisms, which are terminated by a two-sided bevelment, a four-sided, or an eight-sided pyramid.

This species has been divided into two subspecies: 1. fibrous; and, 2. foliated.

Subspecies 1. FIBROUS CELESTINE.

Exter. Char.—Found massive or crystallized; lustre of the longitudinal fracture shining; that of the cross fracture, weakly shining between pearly and refrinous. Longitudinal fracture foliated; cross fracture fibrous, curved; fragments splintery; rather blunt-edged.

Colour indigo blue, bluish gray, and sometimes with whitish bands, or with yellowish brown spots; translucent; soft, and easily frangible. Spec. grav. 3.83.

Constituent Parts. Klaproth.

| Strontites | 58 | | Sulphuric acid and oxide of iron | 42 |

100

Localities, &c.—Has been found in Pennsylvania in America, and near Toul in France.

Subspecies 2. FOLIATED CELESTINE.

Exter. Char.—This is also found massive and crystallized; lustre weakly shining, or shining; that of the crystals resplendent; fracture foliated, straight, or radiated; cleavage threefold.

Colour milk-white, grayish, and bluish-white; semi-transparent, or translucent; semi-hard; very easily frangible.

The following are the constituent parts of a variety of sulphate of strontites, which is found at Mont Martre near Paris.

| Sulphate of strontites | 91.42 | | Carbonate of lime | 8.33 | | Oxide of iron | .25 |

100.00* Locality, &c.—This variety is found in great abundance near Bristol in England, where the sulphate of strontites was first discovered by Mr Clayfield. It has been since found in Sicily, where it is accompanied with fibrous gypsum and native sulphur.

SECOND CLASS. SALTS.

I. Genus. SULPHATES.

1. Species. NATIVE VITRIOL.

Mixed vitriol, or sulphate of iron, copper and zinc. Kirwan, ii. 24. Vitriol Natif, Brochant, ii. 2.

Exter. Char.—This mineral is found massive or disseminated, and also in a stalactitical, cylindrical, and capillary form; internal lustre shining, or weakly shining, between silky and vitreous; external surface rough and uneven; fracture usually fibrous, sometimes foliated.

Colour grayish, or yellowish white, sometimes different shades of sky blue; the colour varies by exposure to the air. Soft; semi-transparent or translucent; taste sour and astringent.

Chem. Char.—These are different, according to the proportions of the constituent parts. Before the blowpipe, sulphurated hydrogen gas is given out; the iron is detected by giving a black colour to the solution of nut galls; the copper, by immersing a plate of iron; and the zinc, by a white efflorescence, which appears when the native salt is exposed to the air.

This substance is a mixed salt, composed of the sulphates of iron, zinc and copper; in variable proportions, so that its appearance and characters must also be variable.

Localities, &c.—Native vitriol is not uncommon in mountains of clay flate which contain metallic ores, and particularly those of copper and iron pyrites, and blends; by the decomposition of which it is formed. It is found in Bohemia, Saxony, and Hungary, as well as in the mines of Britain, where such metallic ores abound.

The native sulphate of iron is common in coal mines which contain iron pyrites, as in many of the coal mines of Britain. This substance is very abundant in the earl of Glasgow's coal mines near Paisley, where the manufacture of copperas, by purifying and crystallizing the native salt, has been long carried on.

Uses.—The mixed substance, native vitriol, can only be employed to any useful purpose, by obtaining the different salts in a separate form. The uses of these salts are well known in various arts, but particularly in dyeing, and some of them in medicine.

2. Species. NATIVE ALUM.

Alum, Kirwan, ii. 13. L'Alun Natif, Brochant, ii. 6. Alumine Sulfate alkaline, Haüy, ii. 387, 388.

Exter. Char.—Native alum is usually found in small capillary crystals, sometimes adhering to other minerals, and very rarely in stalactitical masses. The form of the crystal of alum is the regular octahedron, which is usually obtained artificially. Externally it is dull, or slightly glimmering, but internally shining, with a silky or vitreous lustre; fracture fibrous; very soft; taste astringent.

Chem. Char.—Before the blow-pipe melts easily in its water of crystallization, then froths up, and becomes a white spongy mass.

Alum is a triple salt, a sulphate of alumina and potash. It rarely happens that all the three ingredients exist together in nature. The potash is usually added during the preparation of artificial alum.

According to the examination of native alum by Klaproth, from the alum cavern at Cape Miseno near Naples, it appears that from 1000 lbs. of the material furnished by nature, 470 lbs. may be obtained, having the requisite quantity of potash; and by an addition of potash to promote the crystallization, 290 lbs. more may be obtained. Analyt. Eff. i. 268. The following is the analysis of the aluminous schists from Freywalde by the same chemist.

| Alumina | 15.25 | | Oxide of iron | 7.50 | | Potash | 2.25 | | Sulphuric acid and water of crystallization | 77. |

100.00* * Analyt. Eff. ii. 78.

Localities, &c.—Native alum is found in those places where the aluminous stones, already described, abound, as in the neighbourhood of volcanoes, and in coal mines. An extensive alum manufactory has been carried on for several years with great skill and success, at Lord Gladstone's coal work near Paisley, mentioned above. The materials are obtained from the rubbish in the old wastes, which consists of the aluminous schists from the roof and pavement of the coal. These mines also abound with iron pyrites; and from the decomposition of all these substances the native vitriol and native alum are obtained.

Uses.—The uses of alum in various arts are too well known to require any enumeration.

3. Species. MOUNTAIN BUTTER.

La Beurre de Montagne, Broch. ii. 10.

Exter. Char.—Found massive; internal lustre strongly glimmering, waxy; fracture foliated; fragments blunt-edged.

Colour grayish white, sulphur yellow, or yellowish brown; translucent at the edges; feels greasy; taste astringent.

Localities, &c.—This species is found in similar situations with the former. In its native repository it is nearly as soft as butter, and has something of the appearance, from which it has its name. Perhaps it ought to be considered merely as a variety of the former. The same remark may be applied to another variety called plumose alum.

4. Species. CAPILLARY SALT. Sulphate of Magnesia.

Le Sel Capillaire, Broch. ii. 8. Haar Salz, or Hair Salt, of the Germans.

Exter. Char.—This salt is always found in fine capillary crystals, so closely united together as to form a compact mass; lustre shining, or weakly shining, silky; fracture fibrous. Salts. Colour white, sometimes greenish, grayish, or yellowish; translucent, friable; taste astringent.

Constituent Parts.—This salt was supposed to be a plumose or native alum; but it appears from the analysis of Klaproth, to be a sulphate of magnesia, with a small proportion of iron. We have examined a similar capillary salt from the coal mines near Paisley, which also appeared to be a sulphate of magnesia, but with a greater proportion of sulphate of iron.

Localities, &c.—This native salt is found in similar situations with the former species.

5. Species. Native Epsom Salt, or Sulphate of Magnesia.

Le Sel amer Natif, Broch. ii. 11. Epsom Salt, Kir. ii. 12.

Exter. Char.—The characters already given of the former species are equally applicable to this, excepting that it is said to exist sometimes in an earthy form, when it has a dull appearance.

Localities, &c.—Found in a state of efflorescence on limestone, porphyry, sandstones; and it exists in solution in many mineral waters, as in that of Epsom in England, from which it has its name. This salt also constitutes part of the efflorescence which is observed on walls built with lime.

6. Species. Native Glauber Salt, or Sulphate of Soda.

Glauber Salt, Kirw. ii. 9. Le Sel de Glauber Natif, Broch. ii. 14.

Exter. Char.—This salt is sometimes found massive or earthy, rarely stalactitical or crystallized. The crystals are often acicular, or in irregular, six-sided prisms, terminated by a three-sided pyramid, placed on the lateral edges or sides. Lustrous shining, vitreous; but exposed to the air becomes dull. Fracture uneven; that of the crystals conchoïdal. Fragments blunt-edged.

Colour yellowish or grayish white; opaque or transparent; brittle; taste cooling or bitter.

Localities, &c.—This salt is usually found in the neighbourhood of mineral springs which hold common salt in solution, from the decomposition of which, and the combination of its base with sulphuric acid, it is obtained. It is not unfrequent on the banks of salt lakes, and in a state of efflorescence on sandstone, marl, sometimes on the surface of the ground, and sometimes on walls built with stone and mortar. It is found in most countries in the world.

II. Genus. Nitrates.

1. Species. Native Nitre, or Nitrate of Potash.

Nitre, Kirw. ii. 25. Le Nitre Natif, Broch. ii. 17. Potasse Nitratée, Hauy, ii. 346. Saltpetre.

Effem. Char.—Does not deliquesce, and detonates with a combustible body.

Exter. Char.—This salt is commonly found superficial, in acicular crystals, rarely massive, and more rarely crystallized in six-sided prisms; lustrous shining, vitreous; fracture conchoïdal; fragments sharp-edged.

Colour snow white, grayish or yellowish white; translucent; soft; easily frangible or friable; taste saline.

Constituent Parts. Klaproth.

Nitrate of potash, 42.55 Muriate of potash, .20 Sulphate of lime, 25.45 Carbonate of lime, 30.40 Loft, 1.40

100.00*

Exter. Char. &c.—Native nitre is found in Italy near Molfetta, in Naples, from which that analyzed by Klaproth was obtained, and which is disposed in small beds, or more rarely in veins, on limestone. Native nitre is also not uncommon in Hungary, Spain, France, and Peru, in which latter country, and in the East Indies, where it is very abundant, it is found efflorescent on the surface of the ground at certain seasons of the year.

Uses.—The uses of nitre for some economical purposes, in various arts, in medicine, but particularly in the manufacture of gunpowder, are well known.

III. Genus. Muriates.

1. Species. Rock Salt.

Common Salt, Sal Gem, Kirw. ii. 31. Le Sel de Cuisine, Broch. ii. 20. Soude Muriatée, Hauy, ii. 356.

Effem. Char.—Soluble in water, and divisible into cubes.

This species is divided into two subspecies: 1. foliated, and 2. fibrous rock salt.

Subspecies 1. Foliated Rock Salt.

Le Sel Gemme Lamelleux, Broch. ii. 21. Lamellar Sal Gem, Kirw. ii. 32. Soude Muriatée, Amorphe, Hauy, ii. 359.

Exter. Char.—Usually found massive in considerable beds, sometimes disseminated in large masses, or kidney-form, stalactitical, or crystallized in perfect cubes; surface of the crystals smooth; lustrous shining, vitreous; fracture foliated; cleavage threefold and rectangular; fragments cubic.

Colour grayish, yellowish, or reddish white, flesh or brownish red; transparent or translucent; soft; streak grayish white; taste saline.

Chem. Char.—This salt decrepitates violently when thrown on burning coals.

Constituent Parts.

| Constituent | Kitwan. | Bergman. | |-------------|---------|----------| | Soda | 35 | 42 | | Muriatic acid | 40 | 52 | | Water | 25 | 6 |

The above are the analyses of pure salt; for as it is found in nature, it contains several other ingredients.

Localities, &c.—Foliated rock salt constitutes a peculiar kind of stratiform mountain, in which it usually Part I.

Classification—This salt is a volcanic production, and found deposited in the cavities of lava, as on Vesuvius and Etna, and in the Lipari islands. It is also met with in Iceland, in Persia, and different places of Asia. The substance analyzed by Klaproth was from Tartary. This salt has also been discovered in the neighbourhood of coal mines in Britain, which have been accidentally on fire. Sal ammoniac from Egypt may be considered rather as an artificial production.

IV. Genus. CARBONATES.

1. Species. NATIVE SODA, or Carbonate of Soda.

Natron, Kirw. ii. 6. L'Alkali Mineral, Broch. ii. 30. Soude Carbonatée, Hauy, ii. 373.

Effem. Char.—Soluble in water, and effervesces with nitric acid.

Exter. Char.—Found in small particles, which are usually in the state of powder; is dull and meagre to the touch.

Colour grayish white, or yellowish gray; taste sharp alkaline.

Chem. Char.—Very fusible before the blow-pipe; the solution renders vegetable blues green.

The following are the constituent parts of Egyptian natron or soda, analysed by Klaproth.

| Constituent Parts | Percentage | |-------------------|------------| | Carbonate of soda | 32.6 | | Sulphate of soda | 20.8 | | Muriate of soda | 15 | | Water | 31.6 |

100.0

Localities, &c.—Native soda is found on the surface of the soil, or on the borders of lakes which evaporate during the summer, in Egypt, where it has been long collected, and known under the name of natron. In the neighbourhood of Debreczin in Hungary, it is found efflorescent on a heathy soil; in Bohemia, on a decomposed gneiss rock, where it is annually collected in considerable quantity in the spring of the year. Natron is also found near Naples, in Persia, Bengal, and China. It exists also in solution in many mineral waters.

Uses.—This salt is very extensively employed in many arts.

Another variety of native soda has been described. This is in the form of radiated masses, which are composed of acicular crystals. It seems to be a purer carbonate of soda. The following are the constituent parts according to the analysis of Klaproth.

| Constituent Parts | Percentage | |-------------------|------------| | Soda | 37 | | Carbonic acid | 38 | | Water | 22.5 | | Sulphate of soda | 2.5 |

100.0

2. Species. NATIVE MAGNESIA, or Carbonate of Magnesia.

A pretty pure carbonate of magnesia, discovered by Dr Mitchell; and another which contains an admixture of of silica discovered by Giobert, has been already described under the magnesian genus, species 1. which see.

V. Genus. BORATES.

1. Species. Borax.

Id. Kirw. ii. 37. Borax Natif, Broch. ii. 33. Soude Boratee, Hauy, ii. 366.

Effem. Char.—Taste sweetish; fusible with considerable intumescence into a vitreous globule.

Exter. Char.—This salt is found massive and disintegrated, but most frequently crystallized; the forms are a six-sided prism with the two opposite faces broader; the same prism having its lateral edges truncated, or having its too narrow terminal edges truncated; the crystals are usually imbedded in an earthy mass; surface a little rough, sometimes smooth, and usually covered with a white earthy crust; lustre shining, waxy; fracture foliated.

Colour grayish white, yellowish or greenish; semi-transparent, or only translucent; refraction double; soft; brittle; gritty to the feel. Spec. grav. 1.740.

Constituent Parts.—When borax is purified, it is a compound of soda and boracic acid; but in its native state it is always contaminated with earthy matters.

Localities, &c.—Borax is brought from Persia and Thibet. According to some travellers, it is got from the waters of a lake by evaporation in the open air; but according to others it is ready formed on the borders of the lake, where common salt is also collected.

Uses.—Borax is still farther purified after it is brought to Europe, for the purposes of employing it in the arts, particularly as a flux in metallurgical operations.

2. Species. Boracite, or Borate of Magnesia.

Boracite, Kirw. i. 172. Id. Brochant, i. 589.

Exter. Char.—Always found crystallized: 1. In cubes, having the edges and four of the angles truncated; 2. The cube, having all the edges and angles truncated. When these truncations are increased on the edges, a dodecahedron is nearly formed, or when they increase on the angles, the resulting form is an octahedron. Surface of the crystals smooth, sometimes rough; lustre shining or resplendent; internal lustre shining, resinous; fracture conchoidal; fragments sharp-edged.

Colour ash or yellowish gray, grayish or greenish white; semitransparent or translucent, often opaque; semifluid; rather easily flammable. Spec. grav. 2.56.

Chem. Char.—Melts before the blow-pipe, froths up, and yields a yellowish enamel, on which small rough points appear, and are thrown off like sparks by continuing the heat.

Phys. Char.—Boracite has the property of becoming electric by heat, and exhibiting both kinds of electricity by opposite points. These electric poles are the extremities of the axes of the cube, each axis giving out at one extremity positive, and at the other negative electricity.

Localities, &c.—This mineral has been only found at Lunebourg in Lower Saxony, in a mountain composed almost entirely of foliated gypsum, in which the detached crystals are imbedded.

VI. Genus. FLUATES.

1. Species. Cryolite, or Fluate of Soda and Alumina

Id. Brochant, ii. 505. Alumine Fluatee Alkaline, Hauy, ii. 398.

Exter. Char.—Found massive; lustre shining, vitreous; fracture foliated; fragments cubical.

Colour grayish white; translucent; immersed in water, transparent; semifluid; streak snow-white. Spec. grav. 2.94.

Chem. Char.—Melts in the flame of a candle, and from its easy fusibility it derives its name. It then becomes hard, and is changed into a flag, which is somewhat caustic. Soluble with effervescence in sulphuric acid, and gives out white vapours that corrode glass.

Constituent Parts.

| Klaproth. | Vauquelin. | |-----------|------------| | Soda | 36 | 32 | | Alumina | 23.5 | 21 | | Fluoric acid and water | 40.5 | 47 |

Localities, &c.—Cryolite was brought to Copenhagen from Greenland, but nothing is known of its repository (B).

THIRD CLASS. COMBUSTIBLES.

I. Genus. SULPHUR.

1. Species. NATIVE SULPHUR.

Id. Kirwan, ii. 69. Le Soufre Natif, Brochant, ii. 37.

This species is divided into two subspecies; 1. Common; 2. Volcanic native sulphur.

Subspecies Subspecies 1. Common Native Sulphur.

Exter. Char.—The sulphurous odour when heated; colour yellow.

Exter. Char.—Sulphur is found massive, disseminated in superficial layers, or crystallized. Primitive form of its crystals is an octahedron, whose sides are scalene triangles; the integrant molecule is an irregular tetrahedron. The usual forms of the crystals are, 1. That of the primitive form, in which two four-sided obliquely-angled pyramids are joined base to base, of which the common base is a rhomb, whose two diagonals are as 5 to 4; 2. The same form having its summits truncated; 3. The first form having its summit surmounted by an obtuse four-sided acumenation, set on the lateral faces; 4. Or, having the common face truncated; or 5. Having its obtuse lateral edges truncated; or, 6. Having the obtuse angles of the common base truncated. The crystals are of various sizes, most frequently grouped: surface smooth; lustre resplendent; internal lustre shining, or weakly shining, between resinous and adamantine; fracture fine grained, uneven, sometimes conchoidal or splintery; fragments sharp edged.

Colour yellow, greenish, or grayish yellow; translucent or semitransparent; refraction double; soft; brittle, and very easily frangible; gives out by rubbing a sulphurous smell. Spec. grav. 1.99 to 2.03.

Chem. Char.—Burns with a peculiar blue flame, and gives out a pungent odour, which is well known.

Native sulphur is not always pure; it is often contaminated with earthy matters.

Phys. Char.—Sulphur becomes electric by friction, and its electricity is negative.

Localities, &c.—Native sulphur is most commonly found in stratiform mountains, chiefly in those of gypsum, marl, and compact limestone, and there it exists in the form of nodules. Found also, but rarely, and in small quantity, in the veins of primitive mountains. Sulphur is found in many countries of the world, as in Poland, Hungary, Switzerland, Spain, and Sicily, where the finest crystals yet known are found.

Subspecies 2. Native Volcanic Sulphur.

Exter. Char.—Found massive, in rounded pieces, stalactitical, cellular, or in thin sublimed layers, sometimes also crystallized in confused groups; internal lustre weakly shining or shining; fracture uneven; fragments blunt-edged.

Colour the same as the former, but inclining sometimes a little towards gray; translucent; in other characters it resembles the preceding.

Localities, &c.—As its name imports, this variety is found near volcanoes, where it is sublimed among the lava. The sulphur of Ætna and Vesuvius chiefly, and also that of Iceland, and of some of the islands in the West Indies, is collected, and forms a very important article in commerce.

Uses.—Sulphur is one of the most valuable substances in various arts. It is employed in the bleaching of woollen stuffs and silks; it forms an essential ingredient in gunpowder, and it is the base of sulphureous and sulphuric acid, which are so extensively employed in tanning, hat-making, dyeing, and other arts and manufactures.

II. BITUMINOUS Genus.

1. Species. Petroleum, or Mineral Oil.

Le Naphte, and L’Huile Minérale Commune, Broch. ii. 59. and 60. Naphtha and Petrole, Kirwan, ii. 42. and 43. Bitume Liquide Brune, ou Noiratre, Hauy, iii. 312.

Exter. Char.—Found fluid and somewhat viscid. Colour blackish or reddish brown; almost opaque; feels very greasy; exhales a strong bituminous odour; taste pungent, acid. Spec. grav. 0.708 to 0.854.

Chem. Char.—Burns easily with a dense smoke, and leaves some earthy residue. When exposed to the air it becomes thicker and less fluid.

Its constituent parts are carbon, hydrogen, and a small portion of oxygen.

Localities, &c.—Petroleum is generally found in the vicinity of coal, rising to the surface of the water which flows from coal strata. It is not uncommon in different parts of the world. It is found in Lancashire in England, and at St Catharine’s well near Liberton, in the vicinity of Edinburgh.

Naphtha, which is considered merely as a purer kind of mineral oil, is found in considerable abundance in different parts of Persia, on the shores of the Caspian sea, in Calabria, Sicily, and America. In 1802, a spring of naphtha of a topaz yellow colour, burning easily, and leaving little residue, with a specific gravity of 0.83, was discovered in the state of Parma in Italy, and afforded such a quantity as to be sufficient to illuminate the streets of Genoa.

Uses.—Naphtha has been sometimes employed in the composition of varnish, in that of fire-works, for the purpose of heating rooms, when it is mixed with a small quantity of earth; and in Persia and other countries it is burnt in lamps as a substitute for oil. Formerly it was employed in medicine as a vermifuge.

2. Species. Mineral Pitch.

This is divided into three subspecies; 1. elastic; 2. earthy; and, 3. flaggy.

Subspecies 1. Elastic Mineral Pitch.

Mineral Caoutchouc, Kirw. ii. 48. La Poix Minérale Élastique, Broch. ii. 64. Bitume Élastique, Hauy, iii. 313.

Exter. Char.—Found in masses of different sizes, disseminated, sometimes superficial, or stalactitical; lustre dull, rarely glimmering; internal lustre shining, resinous.

Colour brownish black, hair-brown, often veined yellow; translucent at the edges; soft consistence like elastic gum, and also elastic. It gives out the smell of leather. Spec. grav. 0.902 to 1.23.

Localities, &c.—This mineral was discovered in 1785 in the mine of Odin in Derbyshire in England, where it is accompanied with galena, calcareous spar, heavy spar, fluor spar, and blende.

This substance effaces the marks of black lead on paper, like elastic gum; but stains the paper. Subspecies 2. Earthy Mineral Pitch.

Semicompact Mineral Pitch, or Maltlo, Kirw. ii. 46. La Poix Minérale Terreuse, Broch. ii. 65.

Exter. Char.—Found massive; internally dull; fracture earthy, sometimes uneven; fragments blunt-edged.

Colour blackish brown, sometimes clove brown; streak shining, and darker coloured; very soft; feels greasy; smell bituminous.

Chem. Char.—Burns with much flame and smoke; exhales a strong odour, and leaves carbonaceous and earthy matter.

Localities, &c.—Found in the principality of Neufchatel in Switzerland.

Subspecies 3. Slaggy Mineral Pitch.

Compact Mineral Pitch, Kirw. ii. 46. La Poix Minérale Scoriacée, Broch. ii. 66. Bitume Saïde, Hauy, iii. 313. Asphaltum, or Jews' Pitch, of others.

Exter. Char.—Found massive and disseminated, superficial or stalactitical; lustre resplendent, resinous; fracture conchoidal; fragments sharp-edged.

Colour perfect black, sometimes brownish black; opaque, rarely translucent at the edges; lustre remains in the streak; soft; feels greasy; by rubbing gives out a bituminous odour. Spec. grav. 1.07 to 1.6.

Localities, &c.—This variety frequently accompanies the preceding. It is found at Morsfeld in the Palatinate, at Neufchatel in Switzerland. It is found floating on the surface of the lake Asphaltum in Juda, from which it derives its name of Jews' pitch. It is there collected by the inhabitants of the country as an object of commerce, and at the same time, it is said to diminish the quantity of noxious vapours which it exhales—so noxious that birds flying over it drop down dead, whence it has the name of Dead Sea. This variety of mineral pitch is found in other places, sometimes connected with coal and limestone strata, and sometimes with mineral veins. But the island of Trinidad furnishes the greatest quantity of this substance. In that island there is a pitch lake of about four miles in circumference; but it appears from the information of Mr Spon, in a letter to Mr Tobin of Bristol, by whom this information was communicated, along with a number of specimens to Mr Hatchett, that the substance formerly supposed to be mineral pitch, is nothing more than a porous stone impregnated with that substance; so that what was supposed to be an immense lake of mineral pitch or asphaltum, is only the stone of the country impregnated with bitumen. Mr Hatchett thinks this stone may be arranged in the argillaceous genus *.

3. Species. Amber.

Id. Kirw. ii. 65. Le Succin, Broch. ii. 69. Id. Hauy, ii. 37.

This is divided into two subspecies.

Subspecies 1. White Amber.

Exter. Char.—Found massive, and in rounded pieces; lustre shining or weakly shining; fracture conchoidal; fragments sharp-edged.

Colour yellowish white, or straw-yellow; slightly translucent; soft; easily frangible; by friction, or reducing to powder, it gives out an agreeable odour. Spec. grav. 1.07 to 1.08.

Chem. Char.—Burns with a yellow flame, without melting, giving out at the same time a peculiar odour; leaves very little residue.

Subspecies 2. Yellow Amber.

Exter. Char.—Also found in rounded pieces of various sizes; surface rough and uneven; dull, sometimes glimmering; internal lustre resplendent, resinous; sometimes transparent. In its other external and chemical characters, it resembles the preceding.

Phys. Char.—Amber becomes strongly electric by friction, a property known to the ancients. From the Greek and Latin word elelrum, the term electricity is derived.

Constituent Parts.—Amber is composed of a large proportion of oil, and of a peculiar acid, the succinic, which is obtained by distillation.

Localities, &c.—Amber is found in the vicinity of bituminous wood, but most commonly in the sand on the shores of the ocean, and chiefly on the shores of the Baltic. It is found also in Sweden, France, Italy, and on the east coast of England. Amber frequently contains small parts of vegetables, and entire insects. Of the origin of this substance nothing certain is yet known.

Uses.—The uses of amber for ornamental purposes, are well known. In this country it was formerly in higher estimation than at present. It still forms an important article of commerce in eastern countries.

4. Species. Mellite, or Honey Stone.

Id. Hauy, iii. 335. La Pierre de Miel, Broch. ii. 73. Mellilite, Kirw. ii. 68.

Exter. Char.—Found usually crystallized, in double four-sided pyramids; the surface smooth and shining; internal lustre resplendent, between resinous and vitreous; fracture conchoidal; fragments rather sharp-edged.

Colour honey yellow, sometimes hyacinth red; transparent or translucent; refraction double; soft; brittle. Spec. grav. 1.58 to 1.66.

Chem. Char.—Becomes white before the blow-pipe, and is reduced to ashes, without flame.

Constituent Parts. Klaproth.

| Alumina | 16 | | Mellitic acid | 46 | | Water | 38 |

100

Phys. Char.—Becomes slightly electric by friction.

Localities, &c.—This mineral is hitherto rare. It has been found only in Switzerland, accompanied with mineral pitch, and at Arten in Thuringia, attached to bituminous wood.

5. Species. Brown Coal.

This is divided into five subspecies; 1. common; 2. bituminous wood; 3. earthy coal; 4. alum earth; 5. moor coal. Subspecies 1. Common Brown Coal.

La Houille Brune, Broch. ii. 47.

Exter. Char.—Found massive; lustre shining, resinous; fracture conchoidal; longitudinal fracture flaty; fragments rather sharp-edged.

Colour brownish black, or blackish brown; streak shining; soft; not very brittle.

Chem. Char.—Burns with a blue-coloured flame, and gives out an odour like that of bituminous wood.

Constituent Parts. Hatchett.*

Water which soon came over acid, and afterwards turbid by the mixture of bitumen,

Grains.

Thick brown, oily bitumen, 60

Charcoal, 21

Hydrogen, carbonated hydrogen, and carbonic acid gases, 90

The above is the analysis of 200 grains of Bovey coal by distillation.

Localities, &c.—This variety is not uncommon in many places of Germany. It is found also at Bovey near Exeter in England, from which it is called Bovey coal.

Subspecies 2. Bituminous Wood.

Carbonated Wood, Kirw. ii. 60. Le Bois Bitumineux, Broch. ii. 44.

Exter. Char.—Has a ligneous form, and even sometimes the appearance of branches and roots of trees; glimmering in the principal fracture, in the cros fracture, conchoidal; fragments, splintery, wedge-shaped, or tabular.

Colour commonly light blackish brown, sometimes wood brown; opaque; streak shining; soft, and easily frangible.

Chem. Char.—Burns with a bright flame, and gives out a sweetish, bituminous smell.

Localities, &c.—This variety is found in the same places with the other varieties of coal, and also in places where the more common kinds of coal are rare, or in small quantity, as in the island of Iceland, where it is known by the name of furturbrand; and in the island of Skye in Scotland. It is found also in the coal fields round Edinburgh, and also at Bovey near Exeter, and in various places on the continent.

Subspecies 3. Earthy Coal.

Bois Bitumineux Terreux, Brochant, ii. 45.

Exter. Char.—The confidence of this variety is intermediate between solid and friable; dull, rarely glimmering; fracture earthy.

Colour blackish brown, or liver brown; streak shining; flimsy; very soft.

Localities, &c.—This is found in Saxony, Bohemia, France, and particularly in the vicinity of Cologne, where it is known by the name of umber or Cologne earth, which is employed in the fabrication of colours; and from certain varieties which contain pyrites, alum is extracted.

Subspecies 4. Alum Earth.

This has been already described under the name of aluminous schilfus, in the argillaceous genus.

Subspecies 5. Moor Coal.

La Houille Limoneuse, Brochant, ii. 48.

Exter. Char.—This variety is found massive, and in extensive beds; internally glimmering; cros fracture even, sometimes flat conchoidal; longitudinal fracture flaty; fragments trapezoidal or rhomboidal.

Colour blackish brown, and brownish black; streak shining; soft, very easily frangible.

Localities, &c.—Moor coal is abundant in Bohemia; it is found also in Transylvania, and chiefly among sandstone, limestone, and trap rocks. It seems to approach nearly to earth coal.

6. Species. Black Coal.

This species is divided into six subspecies; pitch, columnar, flaty, cannel, foliated, and coarse coal.

Subspecies 1. Pitch Coal.

La Houille Piciforme, Brochant, ii. 49.

Exter. Char.—Found massive or disseminated; and sometimes parts of vegetables, such as the branches of trees, are observed. Lustre shining, resplendent, resinous; fracture conchoidal; fragments sharp-edged.

Colour perfect black, and the longitudinal fracture sometimes brownish; soft; easily frangible. Specific gravity 1.3.

Localities, &c.—This is one of the most common varieties of coal, and therefore is found in all coal countries.

Uses.—As it is susceptible of a fine polish, it is employed for various ornamental purposes. The substance known by the name of jet, belongs to this variety.

Subspecies 2. Columnar Coal.

La Houille Scapiforme, Brochant, ii. 15.

Exter. Char.—Found massive; in its fracture shining or weakly shining, resinous; fracture more or less perfectly conchoidal; fragments indeterminate.

Colour perfect black, or brownish black. It is composed of distinct concretions, which are columnar, parallel, slightly curved, whose surfaces are smooth and shining; soft, and easily frangible.

Localities, &c.—This is a very rare variety of coal. It is found in the Meißner, near Almerode, in Hesse, in a basaltic mountain.

Subspecies 3. Slaty Coal.

La Houille Schilfeuse, Brochant, ii. 52.

Exter. Char.—Found massive in entire beds; lustre shining, sometimes only weakly shining or glimmering, resinous; principal fracture flaty; cros fracture imperfect conchoidal; fragments in the form of tables; not very sharp-edged. Colour perfect black, often also grayish, rarely brownish black; streak shining; soft, or semi-hard; easily frangible. Specific gravity 1.25 to 1.37.

Localities, &c.—This is the prevailing coal in Britain, as at Newcastle and Whitehaven in England, and in the coal country both in the east and west of Scotland.

Subspecies 4. Cannel Coal.

La Houille de Kilkenny, Brochant, ii. 55. Id. Kirwan, ii. 52.

Exter. Char.—Found massive; lustre weakly shining, resinous; fracture commonly conchoidal, sometimes even foliated; fragments sometimes rhomboidal or cubical.

Colour grayish black; streak shining; soft; easily frangible. Spec. grav. 1.23 to 1.27.

Localities, &c.—This coal accompanies the former in many places of England and Scotland, as at Whitehaven and Wigan in Lancashire in England; in the neighbourhood of Edinburgh; and at Muirkirk, and other places in Ayrshire in Scotland. The coal at Kilkenny in Ireland belongs also to this variety; and from the places where it is found, is called Wigan or Kilkenny coal.

Uses.—Besides being employed as fuel with other kinds of coal, this variety, being susceptible of a fine polish, is cut and formed into various useful and ornamental purposes. It is said that the choir of the cathedral church of Litchfield is covered with plates of this coal alternating with black marble.

Subspecies 5. Foliated Coal.

Le Charbon Lamelleux, Brochant, ii. 54.

Exter. Char.—Found massive; principal fracture resplendent; cros fracture shining; principal fracture more or less foliated; cros fracture somewhat uneven; fragments rhomboidal.

Colour perfect black, and on the sides of the figures superficial colours appear, like the colours of tempered steel, or those of the peacock's tail; easily frangible.

Localities, &c.—This coal is found at Liege, in Saxony, near Dresden, and in some parts of France.

Subspecies 6. Coarse Coal.

La Houille Goffiere, Brochant, ii. 55.

Exter. Char.—Found massive; is weakly shining, resinous; fracture uneven, or more or less flaty; fragments blunt-edged.

Colour grayish black, sometimes brownish black; streak shining; soft; easily frangible.

Localities, &c.—Accompanies the other kinds of coal, whose localities have been already mentioned.

7. Species. Coal Blende.

This is divided into two subspecies, conchoidal and flaty.

Subspecies 1. Conchoidal Coal Blende.

La Houille Eclatante, Brochant, ii. 50. Glanz-kohle of the Germans.

Exter. Char.—Found massive, rarely disseminated; lustre shining or resplendent, approaching to metallic; fracture perfectly conchoidal; fragments not very sharp-edged.

Colour iron black, inclining to brown, or exhibiting the superficial colours like tempered steel; soft; easily frangible.

Chem. Char.—Burns without any flame, leaving a white ash.

Localities, &c.—This variety of coal is very rare. It is found at Newcastle, and at Meißn in Hesse, along with the other varieties of coal.

Subspecies 2. Slaty Coal Blende.

Native Mineral Carbone, Kirw. ii. 49. La Blende Charbonneuse, Brochant, ii. 57. Anthracite, Hauy, ii. 307.

Exter. Char.—Found massive and disseminated; internal lustre shining, or resplendent, and between metallic and vitreous; fracture more or less perfectly flaty; cros fracture flat conchoidal; fragments sometimes cubic, and sometimes in tables.

Colour perfect black, approaching more or less to iron black, or grayish or bluish black; opaque; flimsy, but does not write; soft; rather brittle; very easily frangible. Spec. grav. 1.3 to 1.8.

Chem. Char.—Reduced to powder, and heated in a crucible, this coal gives neither a sulphurous nor bituminous smell, and neither sulphur nor bitumen can be obtained from it. After being long exposed to heat, it consumes slowly without flame, and loses during the process about two-thirds of its weight. The residue is of a blackish gray colour, which shows that the combustion has not been complete.

Constituent Parts.

| Panzenberg | Dolomieu | |------------|----------| | Pure carbone | 90 | 72.05 | | Silica | 2 | 13.19 | | Alumina | 5 | 3.29 | | Oxide of iron | 3 | 3.47 | | Loes | | 8. |

Localities, &c.—This variety has been found in a vein at Schenitz in Hungary, in Pais de Vaud, in a transported rock, which seems to be intermediate between granite and breccia; at Konigsberg in Norway, where it is accompanied with native silver; in Saxony it forms an entire bed in a mountain of clay slate; also found in the island of Arran, and near Kilmarnock in Scotland.

III. GRAPHITE Genus.

1. Species. Graphite, or Black Lead.

Plumbago, Kirw. ii. 58. Le Graphite, Broch. ii. 76. Fer Carbure, Hauy, iv. 98.

This species is divided into two subspecies, scaly and compact.

Subspecies 1. Scaly Graphite.

Exter. Char.—Found massive and disseminated; lustre glimmering or shining, metallic; fracture foliated, conchoidal, choidal, sometimes uneven or flaty; fragments bluntedged, sometimes trapezoidal; commonly appears in distinct granular concretions, which are small or fine grained, with a splintery aspect.

Colour intermediate between bluish black and light iron black; sometimes steel gray, or brownish black; opaque; streak shining; stains and writes; soft; easily frangible; feels greasy.

Subspecies 2. Compact Graphite

Exter. Char.—This subspecies approaches so near to the former in its characters, that it seems difficult to distinguish it. The following characters and circumstances connected with the natural history of graphite, refer to both. Specific gravity 1.987 to 2.456.

Chem. Char.—When exposed to heat in a furnace, it gives out, during combustion, a great proportion of carbonic acid, leaving a residuum of red oxide of iron.

| Constituent Parts | |------------------| | Berthollet. | Scheele. | Vauquelin. | | 90.9 | 90 | 23 * | | Mines, No Iron, | 9.1 | 10 | 2 | | Silica, | - | - | 38 | | Alumina, | - | - | 37 | | 100.0 | 100 | 100 |

Of the above analysis it must be observed, that the two first by Berthollet and Scheele must have been very pure specimens of graphite; and, on the contrary, the specimens analyzed by Vauquelin must have been very impure, containing to a large proportion of earthy matters, and to a small proportion of the proper ingredients of that mineral.

Localities, &c.—This mineral, which is not very common, is found chiefly in primitive mountains. It is met with in Spain, France, Bavaria, and Hungary. In England at Borrowdale near Keswick in Cumberland; and at Craigman, near New Cumnock, in Ayrshire in Scotland, where it is found in detached masses among rocks nearly similar to those which accompany coal.

Uses.—Graphite or black lead is employed for making pencils. The coarser parts are employed in making crucibles. It is also employed for covering cast iron, such as grates, to defend them from rust; and on account of its unctuous property, it is applied to those parts of machines which are subject to friction, for the purpose of diminishing it.

2. Species, Mineral Charcoal.

This substance, which accompanies the other varieties of coal already described, is of a woody texture, and has therefore a fibrous fracture, with somewhat of a shining and silky lustre. It is usually found in thin layers with the other varieties of coal, and perhaps it might be considered as coal less perfectly formed; but in its characters it agrees so much with the varieties of coal blende, that it seems quite unnecessary to make it a separate species.

FOURTH CLASS. METALLIC ORES.

I. PLATINA Genus.

Species. NATIVE PLATINA.

Id. Kirw. ii. 103. Le Platine Natif, Bruch. ii. 86. Platine Natif Ferrifere, Hauy, iii. 368.

Exter. Char.—Of a silver white colour, and infusible.

Exter. Char.—Platina is found in the form of small flat or rounded grains; surface smooth, with shining metallic lustre; streak resplendent.

Colour light steel gray, or silver white; semi-hard; ductile; flexible in thin plates. Spec. grav. 15.601 to 17.7; but when purified, and hammered, 23, and according to some, 24.

Chem. Char.—Is almost infusible without addition, in the focus of a burning glass, or exposed to the action of oxygen gas. It does not amalgamate with mercury, and is only soluble in nitro-muriatic acid.

Localities, &c.—Platina was first brought to Europe by Don Ulloa in 1748. The repository of this metal is not known, and it has been found only in South America, till lately that it was discovered in gray silver ore from the mine of Guadalcanal in Spain. In the analysis of this ore, Vauquelin found the platina to be in the proportion of \( \frac{1}{2} \).

Uses.—Platina is one of the most valuable mineral substances, as, on account of its hardness and infusibility, it may be applied to many of the purposes of gold and iron; and from its properties of being less liable to change when exposed to the air, or to the action of other chemical agents, it answers those purposes in a superior degree.

Platina in its crude state is allowed with other metallic substances. It has been long known that it is accompanied with particles of iron, gold, and some other substances. It contains also an ore of one of the new metals. This is iridium, which is alloyed with osmium, another new metal, both which were discovered by Mr Tennant. This ore is composed of plates; it is not malleable; its specific gravity is 19.5, and it is not acted on by nitro-muriatic acid, which dissolves platina. Rhodium and palladium, two other new metals, are alloyed with platina.

II. GOLD Genus.

Species. NATIVE GOLD.

This species is divided into three subspecies; 1. golden yellow; 2. brass yellow; and, 3. grayish yellow.

Subspecies 1. GOLDEN-YELLOW GOLD.

L'Or Natif, Jaune d'Or, Broch. ii. 89. Native Gold, Kirw. i. 93.

Exter. Char.—Gold is found most frequently disseminated, superficial, or in grains; reticulated, dendritical, capillary, or cellular, often in small plates, more rarely crystallized. The forms of its crystals which have been observed, are small perfect cubes, regular octahedrons, dodecahedrons, double eight-sided pyramids, terminated by four-sided funnits, placed on the Metallic four lateral edges of the pyramids alternately; but the crystals are small and ill defined; the surface is smooth and refulgent; that of the small plates drufy and shining; that of the grains only strongly glimmering; internal lustre weakly shining, metallic; fracture hackly.

This variety presents the perfect colour of gold. It is soft; perfectly ductile, flexible, but not elastic; streak refulgent. Spec. grav. of pure gold 19.25 to 19.64.

Subspecies 2. Brass-yellow Gold.

L'Or Natif d'un jaune de laiton, Broch. ii. 91.

Exter. Char.—This variety is almost always found disseminated in small particles, or superficial; sometimes also capillary, in small plates, or crystallized in thin fixed tables.

The colour is that of brats of various shades, according to the proportion of alloy. In other characters it resembles the former, excepting in the specific gravity, which is inferior, owing to the greater proportion of other metals with which it is alloyed.

Subspecies 3. Grayish-yellow Gold.

L'Or Natif d'un jaun grisatre, Broch. ii. 92.

Exter. Char.—This variety is also found disseminated in small flattened grains; surface is not very smooth; almost uneven, and weakly shining.

Colour steel gray, approaching to that of brats: spec. grav. of this variety is greater than the last, but inferior to the first. In other external characters they are the same.

Chem. Char.—Native gold is only soluble in nitro-muriatic acid; platina is also soluble in the same acid, but it is not like gold, precipitated from its solution by sulphate of iron.

Constituent Parts.—Native gold is not always found pure. It is frequently alloyed with silver or copper, or with both, and sometimes also, it is said, with platina. To these alloys the difference of colour, which is the foundation of the division into three varieties, is owing. The first variety is the purest, containing only a small proportion of silver or copper; the second has a greater proportion of these metals; and the third, it is supposed, is alloyed with a small portion of platina.

Uses.—Gold (on account of its indestructible nature, and its remarkable malleability and ductility), is one of the most important and valuable of the metals for many purposes; but its uses, whether as money, or articles of luxury, are too well known to require enumeration. As pure gold has no great degree of hardness, it is necessary to alloy it with a portion of copper. This is not less than $\frac{1}{2}$ and never more than $\frac{3}{4}$.

Locality, &c.—Gold is chiefly found in primitive mountains, and there it is usually in veins, sometimes disseminated in the rock itself. The accompanying substances are quartz, feldspar, limestone, heavy spar, pyrites, red silver, vitreous silver, and galena. Gold is also mixed with manganese, gray cobalt, nickel, and malachite. Gold has also been found, it is said, in fossil substances, as in petrified wood, penetrated with siliceous earth, a mass of which was dug out at the depth of 50 fathoms, in an argillaceous breccia, or, as is supposed by some, a porphyry with an argillaceous basis, in Transylvania. This is considered as a proof of the more recent formation of gold, as well as the discovery of Patrin, who found native gold surrounded by muriate of silver, in the mine of Zmeof in Siberia. Muriate of silver is supposed to be comparatively a late production.

But gold is perhaps more common to alluvial soil; there it is disseminated in grains, along with siliceous, argillaceous, and ferruginous sand, of which certain soils are composed; and also in the sand of many rivers; and it is observed that the gold is most abundant when the waters are at the lowest, and especially soon after floods, which shows that the gold is carried down along with the earthy matters which are swept away by the violence of the current. It has been supposed too, that the gold found in the bed of rivers, has been detached, by the force of the waters, from the veins and primitive rocks traversed by these currents; and according to this opinion, attempts have been made to trace the source of these auriferous sands, in the hope of discovering the native repository of this precious metal; but these attempts have usually failed, for it has been found that the gold is peculiar to the alluvial soil through which the stream is carried, and in which the gold is collected. This point seems to be established by the observations of naturalists. 1. The soil of those plains frequently contains, to a certain depth, and in particular places, particles of gold, which may be separated by washing. 2. The bed of the rivers and auriferous streams yields a greater proportion of gold, after the plains which are traversed by these rivers have been flooded, than in any other circumstances. 3. It has always been observed, that gold is found in the sand of rivers in a very limited space. By examining the sand of these rivers higher up, and nearer to their source, no gold is found; so that if this metal were derived from the rocks, which are swept by the currents, the quantity would be greatest nearest to their sources; but observation has proved the contrary. Thus the river Orco contains no gold, but from Pont to the place where it joins the Po. The Tefin affords no gold till it has traversed Lake Major, where its course must have been retarded, and where all the heavy particles of matter which it carried along with it from the primitive mountains, must have been deposited. The quantity of the gold collected on the Rhine near Strasbourg, is greater than what is found near Baffe, which is more in the vicinity of the mountains. No gold has been discovered in the sands of the Danube during the first part of its course. Those sands become only auriferous below Effering. The same remark may be applied to the Ems. The sands of the upper part of this river, which traverses the mountains of Stiria, contain no gold; but from the place where it enters the plain at Steyer, till it joins the Danube, its sands are auriferous, and sufficiently rich to be washed with advantage.

The most of the auriferous sands in all parts of the world, are of a black or reddish colour, and consequently ferruginous. From this circumstance, connected with the gold of alluvial land, some naturalists have inferred, that it is owing to the decomposition of auriferous pyrites. It was observed by Reaumur, that the sand which accompanies gold in most of the rivers, and particularly in the Rhone and the Rhine, is like that of Ceylon. The mines of Hungary are the only gold mines in Europe which are of any importance.

In Sweden gold is obtained from the mine of Edelfors in the province of Smoland. This mine yields native gold, and auriferous iron pyrites. The veins are composed of brown quartz, traversing a mountain of schistose hornblende. The gold is sometimes disseminated in the rock itself.

In Greece, the island of Thasos in the Archipelago Greece was celebrated in antiquity for its rich mines of gold. The ancients also, it is said, found abundance of gold in Thrace and Macedonia.

The alluvial soil in several places of the British Isles has also furnished gold. Not many years ago, a considerable quantity of gold was collected in a sandy soil, on the mountains of Wicklow in Ireland. Several masses of native gold, exceeding an ounce in weight, were found in that soil; one weighing 22 ounces was found, which is said to be the largest specimen of native gold found in Europe.

It would appear that gold was collected at a very early period in Scotland, and particularly in the mine field of Leadhills; but the most extensive operations were carried on by Bulmer, an Englishman, in the time of Queen Elizabeth. The trenches, heaps of soil that had been turned up, and other marks of these operations, yet visible between Leadhills and Elvanfoot, still retain the name of Bulmer's Workings, and the place where the gold was washed, is still called the gold scour. At that time, it is said, an immense quantity of gold was collected. Not many years ago, similar operations were resumed by the advice of a German; but so far as we understand, the quantity of gold collected was scarcely equal to the expense. The operations during the last attempt were carried on under the superintendence of the late Mr John Taylor, manager of the mines at Wanlockhead; a man of no common sagacity, by which he was enabled to collect many curious facts with regard to the natural history of gold. The gold was found in that country immediately under the vegetable soil; and the method of conducting the operation was, to direct a small stream of water so as to carry this soil along with it, to basins or hollow places, where the water might deposit the matters which had been carried along by its current. The matter deposited was repeatedly washed, till the whole of the earthy substances were carried off. The gold being heaviest, sunk to the bottom, and remained behind. Among other facts which Mr Taylor communicated to us, and which he observed during the progress of these operations he found, that the gold was always most abundant near the top of the lead veins which traverse that country. He was so satisfied of this fact, that he could tell, merely by the quantity of gold increasing, when they approached to a vein; and on the other hand the quantity diminishing as they receded from the vein. This fact shews that there is some connection between metallic veins and the formation or deposition of gold.

Gold is still found in the soil of that country; but whether the quantity be less than formerly, or the expense of collecting it, from the difference in the price of labour, greater, the produce is by no means equal to the expenses, and therefore searching for gold is now only the employment of the leisure hours of some of the miners. The whole extent of the continent of Asia furnishes gold, in greater or smaller quantity. Gold is found in several of the mines of Siberia, and particularly in that of Bereof, which yields auriferous pyrites partially decomposed, and disseminated in a vein of quartz. In the southern parts of Asia, many mines, and particularly the sands of the rivers, contain gold. The Pactolus, a small river of Lydia, was celebrated in antiquity for the quantity of gold which it yielded, and it was supposed to be the source of the riches of Croesus.

Japan, Formosa, Ceylon, Java, Sumatra, Borneo, the Philippines, and other islands of the Indian Archipelago, are supposed to be rich in gold at this day.

The greatest quantity of gold which the ancients possessed, beside what was obtained from Spain, was brought from Africa. The gold of Africa, which still forms an important article of commerce, is always in the state of gold dust; a circumstance which shows that it is chiefly extracted from alluvial soil by washing. Little gold is found in the northern parts of Africa; three or four places are remarkable for the quantity of gold which they yield. The first is that part of the country between Darfour and Abyssinia. The gold collected there is brought by the Negroes for sale in quills of the ostrich and of the vulture. It would appear that this country was known to the ancients, who regarded Ethiopia as a country rich in gold; and Herodotus mentions that the king of that country exhibited to the ambassadors of Cambyses, all the prisoners bound with chains of gold.

The second great source of gold dust in Africa is to the south of the great desert Zara, in the western part of that country. The gold is collected in that extensive flat which stretches along the foot of the lofty mountains, among which the rivers Senegal, Gambia, and Niger, have their origin. Gold is found in the sands of all these rivers. Bambook, which lies to the north-west of these mountains, supplies the greatest part of the gold which is sold on the western coast of Africa; at Morocco, Fez, and Algiers, as well as that which is brought to Cairo and Alexandria in Egypt.

A third region of Africa where gold is abundant, is on the south-east coast, opposite to Madagascar; and it is said that the gold brought from Ophir, in the time of Solomon, was from that part of Africa.

America is the richest country of the world, in modern times, in this precious metal. There it is collected in the alluvial soil, and in the beds of rivers, and sometimes, but more rarely, in veins. In Mexico, gold is chiefly found in the numerous silver veins of that country. All the rivers in the province of the Caracas, about 15° north of the equator, furnish gold. In the Spanish part of America, Chili furnishes gold from the alluvial soil, as well as the province of Choco, where it is more abundant; while that of Peru is obtained from veins of quartz, marked with ferruginous spots.

But the greatest quantity of gold of commerce comes from Brazil, where it is collected in the alluvial soil, and in the sand of rivers, and extracted by washing. Gold is found almost everywhere in that country, at the foot of the immense chain of mountains which is nearly parallel with the coast, and which stretches from the 5° to the 30° of S. Lat.

### III. MERCURY GENUS

#### 1. Species. NATIVE MERCURY.

**Mercury**, Kirw. ii. 223. *Mercure Natif*, Broch. ii. 241. Id. Hauy, iii. 423.

**Effem. Char.**—Remains liquid till the temperature be reduced to 40° below 0 Fahrenheit.

**Exter. Char.**—Native mercury exists disseminated, in globules of different sizes, in small cavities of other ores of mercury; lustre resplendent, metallic.

Colour shining white, or tin white; opaque; perfectly dry; does not wet the finger; feels very cold. Sp. gr. 13.568 to 13.581.

**Chem. Char.**—Volatile before the blow-pipe, without diffusing any perceptible odour.

Native mercury is understood to be pure, and having all the properties of that metal; but it is sometimes amalgamated with a little silver, which destroys its fluidity in a slight degree, and renders it somewhat viscous.

**Localities, &c.**—Native mercury is usually found along with the other ores of that metal, as at Idria, in Frioul, and at Almaden in Spain; but the great proportion of the mercury of commerce is obtained by distillation from native cinnabar. There is also, it is said, a rich mine of native mercury near Guanca Velica in Peru.

**Uses.**—For many purposes mercury is one of the most important of metallic substances. It is extensively employed in metallurgy, in extracting gold and silver from their ores, by the process to be afterwards described, called amalgamation. The uses of mercury in gilding, in silvering the backs of mirrors, and in medicine, are well known.

#### 2. Species. NATIVE AMALGAM.

**Natural Amalgam**, Kirw. ii. 223. *L'Amalga Natif*, Broch. ii. 99. *Mercure Argental*, Hauy, iii. 432.

**Effem. Char.**—Communicating to copper a silvery colour by friction.

**Exter. Char.**—This species is rarely found massive, but usually disseminated, or superficial, sometimes imperfectly crystallized. The form of its crystals is the octahedron, dodecahedron, but it is usually found in thin plates or leaves; lustre resplendent, or shining; fracture conchoidal.

Colour between shining or tin white, and silvery-white, according to the predominance of the mercury or silver; soft, and partially fluid; brittle, and easily frangible.

**Chem. Char.**—Exposed to heat the mercury is driven off, and the silver remains behind.

| Constituent Parts | Heyer | Cordier | Klaproth | |-------------------|-------|---------|----------| | Mercury | 75 | 73 | 64 | | Silver | 25 | 27 | 36 | | **100** | **100** | **100** | **100** |

**Localities, &c.**—This mineral is rare, and is met with, according to De Born, in the mines of mercury. whose veins are crossed by veins of silver ores. It is found chiefly at Rofenau in Hungary, in Moersfeld, and Mochellanberg, in the duchy of Deux Ponts, and at Sahlberg in Sweden. It is usually found in a yellowish or reddish ferruginous clay, and accompanied by other ores of mercury.

3. Species. CORNEOUS ORE OF MERCURY.

Mercury mineralized by the vitriolic and marine acids, Kirw. ii. 229. La Mine de Mercure corneé, Broch. ii. 101. Mercure muriaté, Hauy, iii. 447.

Exter. Char.—Colour pearl gray, volatilized by the blow-pipe.

Exter. Char.—Rarely found massive or disseminated, but usually in thin crusts, or in small globules, composed of an afflameage of small crystals, which are either perfect cubes, or six-sided prisms, terminated by a four-sided pyramid; a six-sided prism bevelled at the extremity; or an eight-sided prism with four broad and four narrow alternating faces. Crystals shining, sometimes resplendent; internal lustre shining and adamantine; fracture foliated.

Colour smoke gray, ash gray, or grayish white; translucent; tender, and easily frangible.

Chem. Char.—Entirely volatilized before the blow-pipe, without leaving any residuum, and without decomposition.

The constituent parts are about 70% of mercury, 29% of muriatic acid, and a small portion of sulphuric acid.

Localities, &c.—This mineral has only been known about 13 years, and it is hitherto but rare. It was discovered in the mercury mines of the duchy of Deux Ponts by Woulfe, and has been since found at Almaden in Spain, and at Horowitz in Bohemia. The repository is in the cavities of a ferruginous clay, which is mixed with malachite and gray copper ore.

4. Species. LIVER OR HEPATIC ORE OF MERCURY.

Mine de Mercure hépatique, Broch, ii. 104. Hepatic mercurial ore, Kirw. ii. 224. Mercure sulfuré bitumineuse, Hauy, iii. 446.

This is divided into two subspecies, 1. compact, and 2. slaty.

Subspecies 1. COMPACT LIVER ORE OF MERCURY.

Exter. Char.—Found massive or disseminated; lustre glimmering, metallic; fracture even, sometimes fine-grained uneven; fragments blunt-edged.

Colour between lead gray, and cochineal red; colour of the streak deep cochineal red, and shining; tender, and easily frangible. Sp. gr. 7.18 to 7.93.

Subspecies 2. SLATY LIVER ORE OF MERCURY.

Exter. Char.—Found massive; lustre shining and resplendent; in the cross fracture glimmering; lustre in general metallic, but sometimes vitreous; principal fracture slaty, in curved thick leaves; cross fracture compact and even; fragments in plates.

Colour of the preceding, but somewhat darker, and approaching to that of iron; opaque; streak shining; powder between cochineal and scarlet red; tender, and very easily frangible.

Localities, &c.—This is the most common ore of mercury in Idria, where it forms considerable beds, and yields about 60 per cent. of mercury. It is found also, along with other ores of mercury, in Spain and Siberia.

Liver ore of mercury consists of cinnabar, or the fulphuret of mercury, mixed with a portion of indurated bituminous clay. At Idria it is called branderz, or coaly earth, on account of the predominance of the bitumen.

5. Species. CINNABAR.

This species is also divided into two subspecies, common and fibrous.

Subspecies 1. COMMON CINNABAR.

Le Cinnabre Commun, Broch. ii. 107. Dark Red Cinnabar, Kirw. ii. 223. Mercure Sulfuré compaqué, Hauy, iii. 440.

Exter. Char.—Found massive or disseminated, or in superficial layers, or cellular and kidney-form, and also crystallized. Forms of the crystals are, a double four-sided pyramid with truncated summits; a cube having its opposite diagonal angles truncated; a rhomboidal prism; a three-sided prism terminated by a three-sided pyramid, which also is truncated. The crystals, which are usually small, are confusedly grouped together; surface of the rhomboidal prism transparently streaked, of the others smooth; external lustre shining or resplendent; internal the same, or only glimmering, vitreous, or adamantine; fracture foliated, uneven, or rarely splintery; fragments sharp-edged.

Colour cochineal red, carmine red, and in some varieties lead-gray; opaque, rarely translucent at the edges; crystals translucent, or semitransparent; streak shining, scarlet red; tender, and easily frangible. Spec. grav. 6.902 to 7.86.

Chem. Char.—Before the blow-pipe common cinnabar is entirely volatilized with a blue flame, and a sulphureous odour.

| Constituent Parts | Lampadius | |------------------|-----------| | Mercury | 81 | | Sulphur | 15 | | Iron | 4 | | | 100 |

Localities, &c.—This is the most common ore of mercury, and may be considered as the gangue or matrix of the other ores. Found not only in primitive mountains, where it forms beds in clay and chlorite slate, but also in stratiform mountains, and even in alluvial rocks. The mines of Almaden in Spain, of Idria in Friuli, and those of the duchy of Deux Ponts, have furnished the greatest quantity of common cinnabar. It is also found in Bohemia, Saxony, and Hungary, and in small quantity in France.

Subspecies 2. FIBROUS CINNABAR.

Le Cinnabre d'un Rouge vif, Brochant, ii. 111. Bright red Cinnabar, Kirwan, ii. 229. Mercure sulfuré fibreux, Hauy, iii. 440.

Exter. Char.—Found massive, disseminated, or superficial; Metallic Ores.

ficial; lustre glimmering, silky, often also entirely dull; fracture fine grained earthy, or fibrous; fragments blunt-edged.

Colour bright scarlet red, sometimes crimson or aurora red; opaque; streak shining scarlet red; stains; very tender or friable, and very easily frangible.

Localities, &c.—This variety is very rare in a state of purity. According to Hauy, most of the specimens owe their texture to an admixture of radiated sulphuret of iron. It has been found chiefly at Wolfstein in the Palatinate, where it is accompanied by brown iron ore and hematites.

Uses.—Cinnabar is dug out chiefly for the purpose of extracting the metallic mercury. It is employed also as a colouring matter in painting; but the cinnabar used for this purpose is chiefly artificial.

Some other varieties of cinnabar, or sulphuret of mercury, have been noticed by mineralogists, as a native ethiops mineral. This is of a black colour, a loose concretion, and it stains the fingers. It appears to be some bituminous substance penetrated with cinnabar. It is found at Idria.

Alkaline cinnabar of De Born is found at the same place; is of a bright red colour, foliated fracture, with rhomboidal fragments; and supposed to be cinnabar penetrated with an alkaline sulphuret, the odour of which it gives out by friction. Another variety of cinnabar, usually called native vermilion, is in the form of powder. This substance is very rare, but is also sometimes found at Idria.

IV. SILVER Genus.

1. Species. Native Silver.

Id. Kirwan, ii. 108. Id. Brochant, ii. 114. Id. Hauy, iii. 384.

This is divided into two subspecies, common and auriferous.

Subspecies 1. Common Native Silver.

Exter. Char.—Common native silver is usually found disseminated or superficial, under different imitative forms, as dendritic, filiform, capillary, dendritic, reticulated, veined, or in thin plates; and sometimes crystallized, in cubes, octahedrons, rectangular four-sided prisms, double four-sided pyramids with truncated extremities, double three-sided pyramids with truncated angles, and hollow four-sided pyramids. The crystals are small and grouped together in rows, or dendritical, or reticulated; surface smooth; that of the plates drusy, that of dendritic, filiform, and capillary silver; longitudinally streaked; external lustre glimmering or resplendent; internal always glimmering, metallic; fracture hackly; fragments rather sharp-edged.

Colour silvery white, but sometimes on the surface yellowish brown, or grayish black; opaque; soft; perfectly ductile; flexible, but not elastic; streak shining, metallic. Spec. grav. 10 to 10.47.

Chem. Char.—Native silver is soluble in nitric acid, and may be precipitated by muriatic acid, the muriate of silver being insoluble; or by immersing a plate of copper in the solution of nitrate of silver, the silver is reduced, and appears in the metallic state.

Localities, &c.—Native silver is not uncommon in most of the mines which furnish the other ores of that metal. The accompanying substances are usually heavy spar, quartz, calcareous spar, fluor spar, pyrites, blende, cobalt, and galena. Native silver is very abundant in Mexico and Peru, and it is also not uncommon in Siberia, in Germany, France, and was lately discovered in the Herland mine in Cornwall.

Subspecies 2. Auriferous Silver.

Exter. Char.—This variety is rarely found massive, but is usually disseminated in small particles, or superficial, or reticulated, or in thin plates; lustre shining or resplendent; fracture hackly.

Colour between silver white and brass yellow, sometimes approaching to gold yellow; it is soft, perfectly ductile; flexible without being elastic, and its specific gravity is greater than common native silver in proportion to the quantity of gold with which it is alloyed.

Constituent Parts.—Auriferous silver is a compound of silver alloyed with gold, the latter sometimes in very considerable proportion.

Localities, &c.—This mineral is very rare. It is found at Königberg in Norway, disseminated in massive calcareous spar, fluor spar, and rock crystal, accompanied by blende, galena, and pyrites, in a vein which traverses a rock of flaky hornblende. It is also found in Siberia, in granular heavy spar accompanied by vitreous silver ore, vitreous copper ore, and pyrites.

2. Species. Antimonial Silver Ore.

Argent Antimonial, Brochant, ii. 119. Id. Hauy, iii. 391. Antimonial Native Silver, Kirwan, ii. 110.

Effem. Char.—Colour silvery white; brittle.

Exter. Char.—Found massive or disseminated, kidney-form, or crystallized in four-sided oblique prisms, in fixed prisms, sometimes with the lateral edges truncated, in fixed tables, and in cubes, having some of the angles truncated. Surface of the crystals longitudinally streaked; lustre weakly shining, or only glimmering; internal lustre shining or resplendent; fracture foliated.

Colour silvery white, sometimes a superficial colour between yellow, black, and gray, or the colour of tempered steel; streak shining; semihard. Spec. grav. 9-44.

Chem. Char.—Before the blow-pipe it is easily reduced; the antimony is driven off and gives out its peculiar odour, while the pure silver remains behind incrustated with a brown flag, which communicates to borax a green colour.

When antimonial silver is dissolved in nitric acid, a whitish crust, which is the oxide of antimony, soon appears on the surface.

This mineral, as its name imports, is an alloy of silver and antimony, in which sometimes a small portion of iron is observed. The proportions of the two metals seem to be very variable.

Constituent **MINERALOGY**

### Constituent Parts

| Klapproth | Vauquelin | |-----------|-----------| | Silver | 76 | 84 | 78 | | Antimony | 24 | 16 | 22 | | **Total** | **100** | **100** | **100** |

**Localities, &c.**—This ore of silver is accompanied by calcareous spar, heavy spar, native silver, galena, and quartz, in a vein near the duchy of Furltenberg in Swabia. It has also been found in carbonate of lime and heavy spar near Guadalcanal in Spain.

### 3. Species. Arsenical Silver Ore.

*Id. Kirw. ii. iii.* Argent Antimonial Arsenifere, et ferrifere, Hauy, iii. 398.

**Exter. Char.**—Found massive or disseminated, kidney-form or globular, and also crystallized in perfect six-sided prisms; in similar prisms a little flattened, and having the lateral edges rounded; and in acute six-sided pyramids with truncated summits. Lustre weakly shining, sometimes shining; internal lustre shining or resplendent; fracture foliated; fragments sharp-edged.

Colour tin-white, or lead gray, but exposed to the air yellowish, or steel gray; streak shining; soft; brittle.

**Chem. Char.**—Before the blow-pipe the arsenic is driven off in fumes, diffusing the smell of garlic; there remains behind an impure globule of silver.

### Constituent Parts

| Klapproth | |-----------| | Silver | 12.75 | | Arsenic | 35 | | Iron | 44.25 | | Antimony | 4 | | Lofs | 4 | | **Total** | **100.00** |

**Localities, &c.**—This is a rare mineral, which has been found at Andreaeburg in the Hartz, accompanied by native arsenic, red silver ore, galena, brown blende, and calcareous spar.

### 4. Species. Corneous Silver Ore.

*Id. Kirwan, ii. 113.* La Mine Corné, Broch. ii. 127. Argent Muriaté, Hauy, iii. 418.

**Effem. Char.**—The colour of horn; fusible like wax.

**Exter. Char.**—Rarely found massive; sometimes disseminated in globular pieces, often in superficial layers, and very often crystallized. The forms are, the perfect cube, capillary or needle-formed crystals; the crystals are always small, and commonly grouped together. Surface smooth, shining or weakly shining; internal lustre the same; resinous; fracture uneven, or flat conchoidal; fragments blunt edged.

Colour light pearl gray, violet blue, or lead gray; becomes brown or blackish in the air; translucent; sometimes only at the edges; very soft; receives the impression of the nail; ductile, and in thin plates, flexible. Spec. grav. 4.748 to 4.804.

**Chem. Char.**—Corneous silver ore melts very easily before the blow-pipe, giving out a disagreeable smell, and the globule of silver remains.

### Constituent Parts

| Klapproth | |-----------| | Silver | 67.75 | | Muriatic acid | 21 | | Sulphuric acid | .25 | | Oxide of iron | 6 | | Alumina | 1.75 | | Lime | .25 | | Lofs | 3 | | **Total** | **100.00** |

**Localities, &c.**—Muriate of silver is always found at the upper part of the vein, and it is said that it sometimes accompanies organized substances. Leaves of native silver have been found attached to petrifications, at Frankenberg in Hesse; it is supposed that this metallic silver is the result of the decomposition of the muriate of silver. Corneous silver ore is almost always accompanied by vitreous silver, footy silver, brown iron ore; more rarely by native silver, red silver, galena, quartz, and heavy spar. It is found in Peru and Mexico, in the mines of Freyberg in Saxony, at Allemont in France, and in Siberia.

Another variety of muriate of silver has been described by some mineralogists under the name of earthy corneous silver ore; or, according to the fanciful German name, butter-milk earth. This variety has an earthy fracture, owing to a portion of alumina which is combined with it. It is almost friable; the lustre of the streak is resinous, and it feels somewhat greasy.

**Chem. Char.**—Before the blow-pipe it is slightly agglutinated without melting, and small globules of silver exude from the mass.

### Constituent Parts

| Klapproth | |-----------| | Silver | 25 | | Muriatic acid | 8 | | Alumina | 67 | | With a trace of copper | — | | **Total** | **100** |

This variety is found at Andreaeburg in the Hartz. Another variety has been described under the name of alkaline silver ore, which is nothing more than the muriate of silver combined with carbonate of lime.

### 5. Species. Sooty Silver Ore.

*Id. Kirw. ii. 117.* L'Argent Noir, Broch. ii. 132.

**Exter. Char.**—Found massive or disseminated, perforated or corroded; in superficial layers upon other minerals, or in rounded pieces, covered by muriate of silver; consistence intermediate between solid and friable; dull; fracture fine grained earthy; fragments blunt edged.

Colour bluish black, or blackish gray; streak shining, metallic; stains a little; easily frangible.

**Chem. Char.**—Melts easily before the blow-pipe into a flaky mass, which, by continuing the heat, is partially volatilized, and the globule of silver remains. Its constituent parts are still unknown; as it is usually accompanied by vitreous, cornous, and some other silver ores, it is supposed to be a mixture of those ores in different proportions.

Localities, &c.—Found in Saxony, in France, and in Hungary.

6. Species. Vitreous Silver Ore.

Sulphurated Silver Ore, Kirw. ii. 115. L'Argent Vitreux, Brochant, ii. 134. Argent Sulphure, Haüy, iii. 398.

Exter. Char.—Commonly found massive, disseminated, or superficial; sometimes dendritic, filiform, capillary, dendritic, or reticulated, with other forms and impressions. It is also crystallized in cubes, which are either perfect or truncated on the angles or edges; in octahedrons, which are either perfect, or truncated on the angles; in flat, double, three-sided pyramids, the edges of the one corresponding to the faces of the other; in rectangular four-sided prism, terminated by a four-sided pyramid; in equiangular six-sided prisms, terminated at the two extremities by a three-sided pyramid; corresponding alternately to three of the lateral edges, forming the garnet dodecahedron, of which all the lateral edges are sometimes slightly truncated; in broad and flat six-sided prisms bevelled at the extremity, and having the angles at the acute lateral edges truncated. The crystals are commonly small, and grouped together in rows, or in knots, like the steps of a stair; the cube and the octahedron are the most common, and the cube is sometimes hollow. The surface of the crystal is usually smooth, sometimes rough or drusy; lustre between shining and weakly glimmering; internal lustre shining, metallic; fracture conchoidal, sometimes foliated; fragments blunt-edged.

Colour dark lead-gray, steel-gray, or blackish gray, varying by exposure to the air; streak shining; soft; ductile; may be cut with a knife; flexible without being elastic. Spec. grav. 6.929 to 7.215.

Chem. Char.—Before the blow-pipe vitreous silver is reduced to the metallic state, and the sulphur is driven off. By gradually heating it in a furnace, the silver may be dissipated without fusion, and the silver is reduced to the metallic state in a dendritical or capillary form, exactly resembling native silver.

Constituent Parts.

| Constituent Parts | Klaproth. | |-------------------|----------| | Silver | 66.5 | | Sulphur | 12 | | Antimony | 10 | | Iron | 5 | | Copper and arsenic| 5 | | Earthy matters | 1 | | Loes | 5 |

Localities, &c.—Vitreous silver is one of the most common silver ores. It is usually accompanied by heavy spar, calcareous spar, and fluor spar; along with the other ores of silver and lead, cobalt and blende. It is found in Bohemia, Saxony, Norway, Siberia, and South America.

7. Species. Brittle Vitreous Silver Ore.

L'Argent Vitreux Aigre, Brochant, ii. 138.

Exter. Char.—Found massive, disseminated, superficial, or crystallized in equiangular six-sided prisms, the terminal faces being sometimes plane, and sometimes convex or concave; the same prism truncated on its terminal edges, or terminated by a fixed pyramid set on the lateral faces, and having its summit truncated; in equiangular six-sided tables, or in very flat rhomboids. Crystals small, and grouped together; surface smooth, sometimes drusy; prisms longitudinally streaked; lustre shining or resplendent; internal lustre shining, or weakly shining; fracture conchoidal, sometimes uneven; fragments rather sharp-edged.

Colour iron-black, or steel or lead gray; soft; brittle. Spec. grav. 7.208.

Chem. Char.—Before the blow-pipe it melts with difficulty; sulphur, antimony, and arsenic, are partially driven off, and there remains a button of metallic silver, which is not very ductile, accompanied by a brown flag.

Constituent Parts.

| Constituent Parts | Klaproth. | |-------------------|----------| | Silver | 66.5 | | Sulphur | 12 | | Antimony | 10 | | Iron | 5 | | Copper and arsenic| 5 | | Earthy matters | 1 | | Loes | 5 |

Localities, &c.—This is one of the richest silver ores; and it is usually accompanied by red silver ore, vitreous silver ore, some other metallic ores, and various earthy spars. It is pretty common in Saxony and Hungary, but less abundant than vitreous silver ore. It is also occasionally met with in most other silver mines.

8. Species. Red Silver Ore.

Id. Kirw. ii. 122. Id. Broch. ii. 143. Argent Antimoné Sulphure, Haüy, iii. 402.

This is divided into two subspecies; dark red, and bright red silver ore.

Subspecies 1. Dark Red Silver Ore.

Exter. Char.—Found massive or disseminated, superficial, dendritical, or crystallized in equiangular six-sided prisms, which is either terminated by a three-sided pyramid set on the lateral edges, or has its terminal edges truncated, or is terminated by an obtuse six-sided pyramid set on the lateral faces, and having the summit and lateral edges of the pyramid truncated; sometimes the summit of the pyramid is terminated by a second three-sided pyramid, and sometimes the lateral edges of the prism are bevelled. The crystals are small, and variously grouped together, commonly smooth and resplendent, rarely streaked; internal lustre weakly shining, or only glimmering, adamantine, often semiflattened; fracture usually uneven, sometimes conchoidal; fragments rather blunt-edged.

Colour between cochineal red and lead-gray, and sometimes iron black; crystals translucent; in masses opaque; streak but weakly shining, between cochineal red red and crimson red; soft; brittle, and easily frangible.

Spec. grav. 5.56 to 5.58.

Chem. Char.—Before the blow-pipe it decrepitates and flies off before becoming red, and then melts with frothing up; part is volatilized and sublimes in the form of a yellowish white powder, and leaves a button of metallic silver.

Its constituent parts are supposed to be nearly the same as the following.

Localities, &c.—Found in almost all silver mines, and is usually accompanied by other silver ores, as well as different metallic ores.

Subspecies 2. Bright Red Silver Ore.

Exter. Char.—Found massive, disseminated, or fusiform, and very often crystallized. The forms of its crystals resemble some of those of the former, or are simple six-sided pyramids, or acute six-sided pyramids, having the lateral angles alternately acute and obtuse, with the summit surmounted by a three-sided pyramid placed on the obtuse edges of the first; or surmounted by a six-sided pyramid set on the lateral faces. The crystals are sometimes acicular, and are combined together in a fascicular or reticulated form. Surface of the crystals sometimes smooth, sometimes drusy; streaked longitudinally, but the pyramids are streaked transversely or obliquely; lustre resplendent or shining; internal lustre shining or weakly shining and adamantine; fracture conchoidal, or fine grained uneven; fragments rather blunt-edged.

Colour blood red, or light cochineal red, sometimes bluish on the surface; crystals semitransparent; in masses translucent, often opaque; streak aurora red; soft, easily frangible. Spec. grav. 5.44 to 5.59.

Chem. Char.—Melts before the blow-pipe; blackens, and burns with a bluish flame, giving out white fumes with the odour of garlic. A button of nearly pure silver remains behind.

Constituent Parts.

| | Klaproth. | Vauquelin. | |----------------|-----------|------------| | Silver | 62 | 56.67 | | Antimony | 18.5 | 16.13 | | Sulphur | 11 | 15.07 | | Sulphuric acid and water | 8.5 | - | | Oxygen | - | 12.13 |

The garlic smell, which was formerly supposed to be owing to arsenic, arises from the antimony, which is volatilized by the action of the blow-pipe; although, according to Proult, there are ores of red silver which contain sometimes arsenic and sometimes antimony separately, and sometimes the two metals combined. The red colour of this ore is by Thenard ascribed to the antimony in the state of purple oxide.

Localities, &c.—Red silver ore is usually accompanied by native arsenic, other ores of silver, as well as other metallic ores; and it is found in Bohemia, Saxony, France, Spain, and Hungary.

9. Species. White Silver Ore.

Id. Broch. ii. 150. Light Gray Silver Ore, Kirw. ii. 110.

Exter. Char.—Found massive and disseminated; lustre strongly glimmering; fracture even; fragments blunt-edged.

Colour bright lead-gray, or steel-gray; soft; streak shining. Spec. grav. 5.322.

Constituent Parts.—According to some, this mineral is composed of silver, antimony, and sulphur; but according to others, minerals which have been reckoned white silver ores, contain a very considerable proportion of lead, and therefore ought to be arranged among the ores of that metal. Such are the following analyses by Klaproth.

| | Light coloured. | Dark coloured. | |----------------|-----------------|----------------| | Silver | 20.40 | 9.25 | | Lead | 48.06 | 41. | | Antimony | 7.88 | 21.5 | | Iron | 2.25 | 1.75 | | Sulphur | 12.25 | 22. | | Alumina | 7. | 1.75 | | Silica | .25 | - | | Lows | 1.91 | 2.25 |

Localities, &c.—The real white silver ore has been chiefly found in the mine of Himmelfurt, near Freyberg in Saxony, in a gangue of quartz, and accompanied by galena, red silver, and blende.

10. Species. Black Silver Ore.

Exter. Char.—This ore of silver is of a cellular texture; the streak is shining and metallic; it is brittle, and of a black colour; but it can only be known to be a silver ore by obtaining globules of silver under the blow-pipe. It is usually accompanied by vitreous red silver ores. It is supposed that it is some of the other species of silver ores that may have undergone some change from chemical agents. The silver it contains is in very variable proportions.

Localities, &c.—Found in some of the silver mines at Freyberg in Saxony, and Allemont in France. It is common in Peru and Mexico, and it is called by the Spaniards, negrillo.

Besides the silver ores already described, other species have been mentioned by mineralogists, the existence of which has not been distinctly ascertained; as the carbonate of silver of Widenmann and Kirwan, composed of 72.5 parts of silver, 12 of carbonic acid, and 15.5 of carbonate of antimony and oxide of copper; the reddish and greenish black silver ore, also described by Kirwan, which is supposed to be a mixture of native and sulphurated silver. Light lamellar silver ore, composed of alumina, sulphuret of silver, oxide of iron, and manganese.

V. COPPER Genus.

1. Species. Native Copper.

Id. Kirw. ii. 128. Id. Broch. ii. 158. Id. Hauy, iii. 518.

Efren. Char.—Colour reddish yellow, and malleable.

Exter. Char.—Native copper is found massive, disseminated, superficial, or in rounded pieces; also dendritical and capillary, and very often crystallized in perfect... Metallic Ores.

flect cubes, or with truncated edges or angles; double four-sided pyramids; simple and acute three-sided pyramids. Crystals small, and grouped in a dendritical or botryoidal form; lustre shining or weakly shining; internal lustre glimmering or weakly shining; fracture hackly; fragments blunt-edged.

Colour light copper-red, but exposed to the air, yellowish, blackish, or greenish; streak shining; soft, or semifirm; ductile, and flexible, but not elastic. Spec. grav. 7.72 to 8.58.

Chem. Char.—Copper immersed for some time in a solution of ammonia, or volatile alkali, changes it to a beautiful blue colour.

Localities, &c.—Native copper is not a very rare mineral; it is found in many copper mines accompanied by the other ores of copper, as in the copper mines of Siberia, Saxony, Hungary, Sweden, and Cornwall in England.

2. Species. Vitreous Copper Ore.

Id. Kirw. ii. 144. Id. Broch. ii. 162. Cuivre Sulfuré, Hauy, iii. 551.

This is divided into two subspecies; compact and foliated.

Subspecies 1. Compact Vitreous Copper Ore.

Exter. Char.—Found massive or disseminated, sometimes superficial, and rarely crystallized in perfect cubes with convex faces; in perfect octahedrons, or in six-faced prisms, terminated by a three-sided pyramid, set on three of the lateral edges. Crystals small; surface smooth and shining; internal lustre strongly glimmering or shining; fracture rhombohedral or even, fragments rather sharp-edged.

Colour lead-gray, iron gray, or yellowish, but sometimes the colour of tempered steel when tarnished; streak shining or resplendent; soft, and easily frangible. Spec. grav. 4.81 to 5.338.

Constituent Parts. Klaproth.

| Copper | 78.5 | |--------|------| | Sulphur | 18.5 | | Iron | 2.25 | | Silica | .75 |

100.00

Subspecies 2. Foliated Vitreous Copper Ore.

Exter. Char.—Always found massive or disseminated, rarely superficial; fracture foliated; fragments blunt edged.

Colour similar to the former, approaching a little more to fawn or yellowish brown.

Constituent Parts. Klaproth.

| Copper | 50 | |--------|----| | Sulphur | 20 | | Iron | 25 | | Lofs | 5 |

100

Chem. Char.—Vitreous copper ore is often fusible in the flame of a candle, and it melts easily before the blow-pipe, and yields a button of copper enveloped in a blackish flag; heated with borax, gives it a green colour, and digested in a solution of ammonia, changes it to a fine blue.

Localities, &c.—Vitreous copper ore is accompanied by quartz, calcareous spar, heavy spar, and the other ores of copper; and is common in Siberia, Hungary, Norway, Germany, and Cornwall in England.

3. Species. Variegated Copper Ore.

Purple Copper Ore, Kirwan, ii. 142. La Mine de Cuivre Panachée, Brochant, ii. 166. Cuivre Pyriteux Hépatique, Hauy, iii. 536.

Exter. Char.—Found massive, disseminated, or superficial, and sometimes, it is said, crystallized in octahedrons; internal lustre shining; fracture conchoidal, or somewhat uneven; fragments rather sharp-edged.

Colour reddish yellow, violet blue, azure blue, and greenish; several colours exist on the same specimen, giving it a variegated appearance, from which it has the name; streak shining; powder reddish; soft, and easily frangible.

Constituent Parts. Klaproth.

| Copper | 63.7 | |--------|------| | Iron | 12.7 | | Sulphur | 19 | | Oxygen | 4.5 | | Lofs | .1 |

100.00

Localities, &c.—Variegated copper ore is accompanied by quartz, calcareous spar, bituminous marly schistus, and other copper ores; and is found in Saxony, Hungary, Sweden, Siberia, and England.

4. Species. Copper Pyrites.

Id. Kirwan, ii. 140. Id. Brochant. ii. 169. Id. Hauy, iii. 529.

Exter. Char.—Found massive, disseminated, sometimes superficial, more rarely in imitative forms, as dendritical, &c., but often crystallized. Forms are, the tetrahedron, which is either perfect, or with its four angles truncated, giving it the appearance of a six-sided table; the perfect octahedron, the summit terminated by a line; a double crystal formed of two tetrahedrons base to base, the angles of the bases being slightly truncated, produce three re-entering angles, and the lateral faces three salient angles. Crystals are small; surface smooth, shining; internal lustre shining or resplendent; fracture often uneven, sometimes conchoidal, fragments rather sharp-edged.

Colour in the fresh fracture, brass yellow, sometimes gold yellow, and steel gray; sometimes with variegated colours; soft or semi-hard; brittle. Spec. grav. 4.08 to 4.3.

Chem. Char.—Before the blow-pipe it decrepitates; gives out a sulphureous odour; fuses into a black globule, and the heat being continued, metallic copper appears. Borax heated with it acquires a green colour. This ore of copper is composed of sulphur, copper, and iron in variable proportions, and sometimes also a small admixture of gold or silver.

**Localities, &c.—** This is a very common copper ore. It is equally found in primitive and stratiform mountains, either in veins or in beds, and sometimes in great abundance; in Saxony, Hungary, Sweden, France, and England.

5. Species. **White Copper Ore.**

*Id. Kirwan, ii. 152.* *Id. Brochant, ii. 173.*

**Exter. Char.**—Found massive or disseminated; internal lustre weakly shining; fracture fine grained, uneven; fragments rather sharp edged.

Colour between silver white and brass yellow; semi-hard; brittle. Spec. grav. 4.5.

**Chem. Char.**—Before the blow-pipe it gives out a white fume, with the smell of arsenic, and melts into a grayish black flag.

This ore is said to be composed of copper, iron, arsenic, and sulphur.

6. Species. **Gray Copper Ore.**

*Id. Kirwan, ii. 146.* *Id. Brochant, ii. 175.* *Id. Hauy, iii. 537.*

**Exter. Char.**—Found massive or disseminated, superficial, and often crystallized in regular tetrahedrons, which are rare; or having all the edges truncated, or bevelled, sometimes slightly, and sometimes strongly; or having each of its angles surmounted by a three-sided pyramid, set on the lateral faces, with some other modifications. Crystals of various sizes; surface smooth, shining; internal lustre between glimmering and resplendent; fracture uneven, or conchoidal; fragments rather sharp-edged.

Colour steel gray of various shades, lead gray, and the tarnished colours are often variegated; streak black or brown; semi-hard; brittle. Specific gravity 4.44 to 4.86.

**Chem. Char.**—Before the blow-pipe it decrepitates, and melts into a brittle metallic globule of a grayish colour, giving out a white fume, and communicating to borax a yellowish red colour.

| Constituent Parts. Klapproth. | |-----------------------------| | Copper, | 16.25 | 31.36 | | Sulphur, | 10. | 11.5 | | Antimony, | 16. | 34.09 | | Silver, | 2.25 | 14.77 | | Iron, | 13.75 | 3.3 | | Lead, | 34.5 | | | Silica, | 2.5 | | | Alumina, | | 0.3 | | Lofs, | 4.75 | 4.68 | | | 100.00 | 100.00 |

**Localities, &c.—** This mineral is most frequently found in veins in primitive mountains, accompanied by other ores of copper, as in Germany, France, Sweden, Siberia, and in England.

7. Species. **Black Copper Ore.**

*Id. Kirwan, ii. 143.* *Id. Brochant, ii. 180.*

**Exter. Char.**—Found in the state of powder, with a dull appearance, and little coherence, sometimes incrusting other ores of copper; usually friable; stains; feels meagre.

Colour brownish black, sometimes deep brown.

**Chem. Char.**—Gives out before the blow-pipe a sulphureous smell, and melts with borax into a greenish flag.

It is supposed to arise from the decomposition of vitreous copper ore and copper pyrites, and contains sometimes from 40 to 50 per cent. of copper.

8. Species. **Red Copper Ore.**

*Id. Kirwan, ii. 135.* *Id. Brochant, ii. 181.*

This is divided into three subspecies; compact, foliated and capillary.

**Subspecies 1. Compact Red Copper Ore.**

**Exter. Char.**—Found massive, disseminated, or superficial; lustre glimmering, semi-metallic; fracture even, or slightly conchoidal; fragments rather sharp edged.

Colour cochineal red, or lead gray; opaque; streak shining, of a brick red colour; semi-hard, and brittle.

**Subspecies 2. Foliated Red Copper Ore.**

**Exter. Char.**—Found massive, disseminated, or superficial, often crystallized in octahedrons, which are either truncated on the angles or edges; in perfect cubes, which are sometimes truncated on the angles, and sometimes on the edges. Crystals small, usually aggregated; surface smooth, shining; internally shining, or weakly shining, between metallic and adamantine; fracture imperfectly foliated; fragments rather sharp edged.

Colour similar to the former; opaque, translucent at the edges; crystals semi-transparent.

**Subspecies 3. Capillary Red Copper Ore.**

Fibrous Red Copper Ore, Kirwan, ii. 137. *Le Cuivre Oxidé Rouge Capillaire*, Brochant, ii. 184.

**Exter. Char.**—Found in small capillary crystals, which are disseminated in small bundles, or sometimes form a superficial incrustation; lustre shining and adamantine.

Colour carmine red, cochineal or scarlet red; crystals translucent.

**Chem. Char.**—Red copper ore is easily reduced before the blow-pipe without any odour; entirely soluble in muriatic acid without effervescence, but effervesces in nitric acid; by which means it may be distinguished from cinnabar, which is insoluble, and from red silver ore, which dissolves with effervescence.

The constituent parts of red copper ore are supposed to be copper and oxygen, and not a carbonate of copper, as was formerly conjectured.

**Localities, &c.—** Red copper ore is found in various places accompanying the other ores of the same metal, and and particularly native copper. The crystallized varieties are rare.

9. Species. Brick-red Copper Ore.

Id. Kirwan, ii. 127. Id. Brochant, ii. 187.

Of this also there are two subspecies, earthy and indurated.

Subspecies 1. Earthy Brick-red Copper Ore.

Exter. Char.—Found massive or disseminated, or superficial, in the fissures of other copper ores, composed of fine earthy particles slightly cohering; dull, friable, and shining.

Colour hyacinth red, reddish brown, brownish red, or yellow.

Subspecies 2. Indurated Brick-red Copper Ore.

Exter. Char.—Found massive, disseminated, or superficial; lustre glimmering, or weakly shining; fracture imperfectly conchoidal, even or earthy; fragments rather sharp edged.

Colour deep hyacinth red, brownish red, or deep brown; streak shining; soft, or semifirm; brittle.

Chem. Char.—Before the blow-pipe it is infusible and blackens.

The constituent parts of this ore are supposed to be a mixture of red copper ore, or oxide of copper, and brown oxide of iron, in variable proportions.

Localities, &c.—This ore is usually found accompanying red copper ore.

10. Species. Emerald Copper Ore.

Dioplofs, Hauy, iii. 136. Id. Brochant, ii. 511.

Effem. Char.—Divisible into an obtuse rhomboid, whose plane angles are 111° and 69°.

Exter. Char.—Found crystallized in six-sided prisms, terminated by a three-sided summit, placed on the three alternate lateral edges; lustre shining, vitreous; fracture foliated; cleavage threefold, parallel to the lateral edges of the summit.

Colour emerald green; translucent, or semi-transparent; semi-hard. Spec. grav. 3.3.

Chem. Char.—Infusible before the blow-pipe, but becomes brown, and tinges the flame of a candle yellowish green.

Constituent Parts. Vauquelin.

Oxide of copper, 28.57 Silica, 28.57 Carbonate of lime, 42.85 Loes, .01

100.00

Localities, &c.—This mineral is found in Siberia, in a matrix covered with malachite.

11. Species. Azure Copper Ore, or Carbonate of Copper.

Blue Calciform Copper Ore, Kirwan, ii. 129. L'Azur de Cuivre, Brochant, ii. 190. Cuivre Carbonaté Bleu, Hauy, iii. 562.

This species is divided into two subspecies, earthy and indurated.

Subspecies 1. Earthy Azure Copper Ore.

Exter. Char.—Rarely found massive, usually disseminated or superficial; composed of fine particles which are dull and somewhat coherent; fracture earthy.

Colour smalt blue, sometimes sky blue; opaque; stains a little; soft or friable.

Subspecies 2. Indurated or Radiated Azure Copper Ore.

Exter. Char.—Rarely found massive, sometimes disseminated, often superficial, or in imitative forms, as stalactitical, botryoidal, &c., and also crystallized in rectangular four-sided prisms, terminated by four-sided acute pyramids set on the lateral edges; in oblique four-sided prisms, with two broad and two narrow faces, with a four-sided pyramid set on the lateral faces; sometimes the lateral edges are truncated, and the termination is by a five-sided pyramid. Crystals usually small, and variously aggregated; broad faces of the prisms transversely streaked; narrow faces longitudinally; lustre shining or resplendent, vitreous; fracture radiated; fragments blunt-edged, or wedge-shaped.

Colour light azure blue, Prussian or indigo blue; translucent or semi-transparent; streak sky blue; soft; brittle. Spec. grav. 3.4 to 3.68.

Chem. Char.—Soluble with effervescence in nitric acid; nearly infusible before the blow-pipe, but is easily reduced with borax, which affumes a fine green colour.

Constituent Parts. Pelletier.

Copper, 66 Carbonic acid, 18 Oxygen, 8 Water, 2 Loes, 6

100

Localities, &c.—This variety of copper ore is not very abundant; but it accompanies the other ores of copper, and other metallic ores, as those of lead, zinc, and iron. It is found in Bohemia, Norway, Siberia, and in the different mines of lead and copper in Britain.

The earthy variety is found in superficial layers on a flat marl in Hesse, and it is also found superficial on sandstone in Thuringia. Sometimes the whole of the sandstone is impregnated with this earthy carbonate of copper, there called copper sand earth, or copper sandstone. A similar sandstone, at Gourock near Greenock in Scotland, was a few years ago dug out for the purpose of extracting copper.

12. Species. Malachite.

Id. Kirwan, ii. 131. Id. Brochant, ii. 197.

This species is divided into two subspecies, fibrous and compact.

Subspecies. Subspecies 1. Fibrous Malachite.

Cuivre Carbonaté Vert Soyeux. Hauy, iii. 573.

Exter. Char.—Rarely massive, sometimes disseminated, but often superficial, and in the form of small capillary or acicular crystals grouped together in different forms; lustre shining, or when massive glimmering; internal lustre weakly shining, silky; fracture fibrous, straight, or radiated; fragments blunt edged.

Colour, emerald or apple green; opaque; streak of a lighter colour; soft; brittle.

Subspecies 2. Compact Malachite.

Exter. Char.—Sometimes found massive, disseminated or superficial, but most frequently globular, botryoidal, stalactitical, &c.; surface rough or druzy, sometimes smooth, almost always dull, and rarely shining; internal lustre dull or weakly shining; fracture conchoidal; fragments rather sharp-edged or wedge shaped.

Colour emerald green, apple green, and blackish green; opaque; soft; brittle. Spec. grav. 3.57 to 3.64.

Chem. Char.—Decrepitates before the blow-pipe, and blackens without fusion; effervesces with acids; colours borax green, and communicates a blue colour to the solution of ammonia.

Constituent Parts. Klaproth.

| Compact Malachite. | |-------------------| | Copper, | .58 | | Carbonic acid, | 18 | | Oxygen, | 12.5| | Water, | 11.5|

Localities, &c.—Both the fibrous and compact malachites are usually found in the same repository, and accompanied with other ores of copper. They are found in Germany, but the finest specimens are brought from Siberia. Scotland affords fibrous malachite in small quantity, as at Leadhills and in Shetland. Malachite is also met with in Cornwall and Derbyshire in England.

Uses.—Malachite, when pure, is sometimes employed as a pigment. The compact variety is susceptible of a fine polish; which, with its beautiful and delicate colours, has brought it into much estimation for various ornamental purposes.

The largest and finest specimen of compact malachite known, is in the cabinet of Dr Guthrie at Peterburgh. It is 32 inches long, 17 broad, and two inches thick. It is estimated, according to the account of Patrin, who describes it, at 20,000 francs, above 800l. sterling. If we are rightly informed, this splendid mass of malachite was once offered to sale in Britain, but, having found no purchaser, was carried back to Russia.

13. Species. Green Copper Ore.

Mountain Green, Kirw. ii. 134. Id. Broch. ii. 203.

Exter. Char.—Found massive or disseminated, but usually superficial on other ores; dull; fracture conchoidal or uneven; fragments blunt-edged.

Colour verdigris green, emerald green, sometimes sky blue, opaque, or translucent at the edges; soft, or friable; brittle.

Chem. Char.—Becomes black before the blow-pipe without fusion. Colours borax green.

Constituent Parts.—Supposed to be a mixture of oxide of copper, or according to others, a carbonate, with alumina and lime.

Localities, &c.—It is usually accompanied by gray copper ore, and some other copper ores, particularly with malachite, and sometimes with iron ochre, alumina, and quartz. Found in Saxony, Hungary, and Siberia.

14. Species. Ferruginous Green Copper Ore.

This is divided into two subspecies; 1. earthy; and, 2. flaggy.

Subspecies 1. Earthy Ferruginous Green Copper Ore.

Iron-shot Mountain Green, Kirw. ii. 155. Id. Broch. ii. 205.

Exter. Char.—Found massive; but most frequently disseminated; dull, with an earthy fracture; fragments blunt-edged.

Colour light olive green; soft, friable; brittle; meagre to the feel.

Subspecies 2. Slaggy Ferruginous Green Copper Ore.

Flaggy Iron-shot Mountain Green, Kirw. ii. 152.

Exter. Char.—Massive, or disseminated; lustre shining, vitreous; fracture conchoidal; fragments sharp-edged.

Colour deep olive green, sometimes black; soft; brittle.

Constituent Parts.—Seems to be a mixture of oxide of copper with iron ochre, in variable proportions.

Localities, &c.—Found along with other copper ores, and is accompanied by iron ochre, heavy spar and quartz. It is a rare mineral. Has been found in Saxony, and it is said in the Hartz.

15. Species. Micaceous Copper Ore, or Arseniate of Copper.

Olive Copper Ore, Kirw. ii. 151. Le Cuivre Arsenical, Broch. ii. 228. Cuivre Arseniate. Hauy, iii. 575. Arseniate of Copper, Bourdon, Phil. Trans. 1801. p. 193.

This species is divided into two subspecies, foliated and lenticular.

Subspecies 1. Foliated Micaceous Copper Ore.

Exter. Char.—Found massive, disseminated, or crystallized in oblique four-sided prisms, in six-sided prisms, in acute rhomboids, or in very small cubes. These crystals are also variously modified; lateral faces streaked longitudinally; lustre resplendent, pearly, or adamantine; fracture foliated, sometimes conchoidal.

Colour olive green, sometimes emerald green, or verdigris. digris green; translucent; crystals semitransparent; soft. Spec. grav. 2.54.

Subspecies 2. LENTICULAR MICACEOUS COPPER ORE.

Exter. Char.—This variety is found crystallized in octahedrons, composed of two four-sided pyramids, with isosceles triangular faces; crystals small; external lustre shining; fracture foliated.

Colour fky blue, or verdigris green; feratches calcareous spar; brittle; easily frangible. Spec. grav. 2.88.

Chem. Char.—The crystals of these varieties decrepitate before the blow-pipe, and give out the odour of arsenic. They melt into a grayish globule, which being treated with borax, yields a button of copper.

Constituent Parts. Vauquelin.

| Oxide of copper | 39 | | Arsenic acid | 43 | | Water | 17 | | Loes | 1 |

Localities, &c.—These varieties of copper ores are very rare; and have been hitherto discovered only in the Carrara mine, Cornwall, accompanied by brown iron ore and other copper ores.

Other arseniates of copper have been described by Bourdon. In many respects they resemble the preceding varieties. The spec. grav. which is 4.28, is considerably greater, and yet the proportions of the constituent parts approach very near.

Constituent Parts. Chenevix.

| Oxide of copper | 50 | | Arsenic acid | 29 | | Water | 21 | | Loes | 2 |

Count de Bourdon has described another, under the name of cupromartial arseniate, which is also crystalized, has a spec. grav. 3.3, and the following are its constituent parts.

| Oxide of iron | 27.5 | | Copper | 22.5 | | Arsenic acid | 33.5 | | Silica | 3 | | Water | 12 | | Loes | 1.5 |

16. Species. MURIATE OF COPPER, or Green Sand of Peru.

Id. Broch. ii. 149. Id. Broch. ii. 545.

Exter. Char.—Found massive, or crystallized in very small six-sided prisms, bevelled at the extremities, or in small oblique four-sided prisms, also bevelled at the extremities, but the sides corresponding to the obtuse lateral edges; surface of the crystals smooth and re-

splendent; lustre adamantine; fracture foliated; fragments rather sharp-edged.

Colour between emerald and leek green; opaque; crystals a little transparent; streak pale apple green. Spec. grav. 3.57 to 4.43.

Chem. Char.—Thrown on burning coals, it communicates a green colour to the flame; soluble in nitric acid without effervescence.

Constituent Parts.

| Profl. | Klaproth. | | Oxide of copper | 76.6 | 70.6 | 73. | | Muriatic acid | 10.6 | 11.4 | 10.1 | | Water | 12.8 | 18.1 | 16.9 |

Localities, &c.—This mineral has been found in the sand of rivers, accompanied by quartz, schorl, copper and iron ores, near Remolinos in Chili. It has also been found in a similar situation in Peru.

PHOSPHATE OF COPPER.—This mineral has been found massive, or crystallized in oblique six-sided prisms, with convex faces, lining cavities; lustre refulgent, between vitreous and adamantine; internal lustre silky; fracture fibrous.

Colour grayish black, but internally emerald green; opaque; streak apple green; soft, or semifirm.

Constituent Parts. Klaproth.

| Oxide of copper | 68.13 | | Phosphoric acid | 30.95 | | Loes | .92 |

Localities, &c.—This mineral has been found near Bologna, along with malachite, in a white drusy quartz.

COPPER MINES.—In addition to the history of copper ores now given, we shall just name some of the more celebrated copper mines in the world. The copper mines of Spain are situated on the frontiers of Portugal, and yield from veins of considerable thickness, yellow pyrites. France possesses copper mines in the Pyrenees, near Lyons, in Vosges, and in the neighbourhood of Savoy, in the department of Mont Blanc. There are extensive copper mines in Piedmont, which have been wrought to a very considerable depth.

The copper mines of Cornwall in England, which are in primitive rocks, have been long celebrated. The most abundant ores are copper pyrites, accompanied by native copper, which latter, it is observed, is most usually found near the surface. The same mines yield all the varieties of arseniate of copper. The Aston copper mines on the borders of the counties of Derby and Stafford are situated in limestone, in very declining or nearly perpendicular beds; but the richest copper mines in England are those of the island of Anglesea, where is a mass of pyritous copper ore of immense thickness, yielding from 16 to 40 per cent. of copper. Native copper is also found near the surface, and immediately under the turf. The mines of Cronebane, in the county of Wicklow in Ireland, are very considerable. They are situated in a primitive mountain, composed of flinty slate and argillaceous schistus, which alternate with beds of steatites.

In Germany, Hungary, Sweden, Norway, and Siberia, there are many extensive and valuable copper mines. In the eastern parts of the Asiatic continent, in the island of Japan, in China, and in some of the islands of the Indian ocean, rich copper ores are abundant.

Africa, in various places of that extensive region, abounds with ores of copper, as in the mountains to the north of the Cape of Good Hope. On the western coast of Africa, the natives dig out copper ore, and are acquainted with the mode of extracting it.

In North America masses of native copper have been found, near Hudson's Bay; but the richest copper mines in the world are those of South America, and particularly in Chili, from which masses of native copper of immense magnitude have been obtained. The copper mines of Peru and Mexico are also wrought to great advantage.

VI. IRON Genus.

1. Species. NATIVE IRON.

Id. Kirw. ii. 156. Id. Brochant, ii. 215. Id. Hauy, iv. 1.

Exter. Char.—Found massive or branched; surface smooth, shining; internal lustre shining, metallic; fracture hackly; fragments rather sharp-edged.

Colour light steel gray, or silvery white; semi-hard; streak shining; perfectly ductile; flexible; but not elastic.

Locality, &c.—The existence of native iron as a terrestrial production still remains doubtful. It is said that it has been found along with other ores of iron, in Saxony and in France. The only instances fully established of the discovery of native iron, are those of the immense mass found by Pallas in Siberia, which amounted to no less than 168 cwt. or 15 cwt., and another of 3 cwt., which was discovered by Rubin de Celis in South America; but these masses correspond so nearly with the substances which are certainly known to have fallen from the atmosphere, in their constituent parts, that it seems extremely probable they have had a similar origin. But for a full account of this curious subject, see Meteorite.

2. Species. IRON PYRITES.

Marital Pyrites, Kirwan ii. 76. Id. Brochant, ii. 221.

Fer sulfure, Hauy, iv. 65.

Subspecies 1. COMMON IRON PYRITES.

Exter. Char.—Found massive or disseminated, superficial, or in imitative forms, and frequently crystallized. The forms are, a perfect cube with plane or convex faces; or with truncated angles, or edges; or having a three-sided pyramid on each angle; the perfect octahedron, or truncated on all its angles; the dodecahedron with pentagonal faces, or with six opposite and parallel edges truncated, or truncated on eight of its angles; or the perfect icosahedron, which is rare.

Crystals small, excepting the cube, and grouped together; surface smooth or streaked; lustre thinning, resplendent; internal lustre shining, metallic; fracture uneven; sometimes conchoidal; fragments rather sharp-edged.

Colour bronze yellow, golden yellow, sometimes steel gray; opaque; hard; brittle; rather easily frangible.

Spec. grav. 4.6 to 4.83.

Chem. Char.—Before the blow-pipe it gives out a strong sulphurous smell, and burns with a bluish flame; a brownish globule is then obtained, which is attracted by the magnet.

Constituent Parts. Hatchett.

| Sulphur | 52.15 | 52.5 | |---------|-------|------| | Iron | 47.85 | 47.5 |

100.00 100.0

Some varieties of common iron pyrites contain a mixture of gold, which is supposed to be accidental, as the external characters are not affected by it, and it is only recognized by chemical analysis. These varieties are called auriferous pyrites.

Subspecies 2. RADIATED IRON PYRITES.

Exter. Char.—Found massive, or in different imitative forms, and also crystallized in small cubes or octahedrons; surface smooth or druly; lustre shining or resplendent; fracture radiated; fragments wedge-shaped.

Colour bronze yellow, lighter than the former; sometimes steel gray, and sometimes tarnished; hard; brittle, and easily frangible.

Subspecies 3. CAPILLARY IRON PYRITES.

Exter. Char.—Found in small, capillary, or acicular crystals, having the appearance of flocks of wool; sometimes the crystals are acicular or in a flatted form; lustre thinning or weakly shining, metallic.

Colour bronze yellow, approaching to steel gray.

Subspecies 4. HEPATIC IRON PYRITES.

Exter. Char.—Massive or disseminated, or in different imitative forms, as stalactitical, cellular, &c.; sometimes crystallized in perfect six-sided prisms or in six-sided tables, which are either perfect or bevelled on the terminal faces. Crystals small; sometimes smooth; sometimes druly; internal lustre glimmering, or weakly shining; fracture even, or imperfectly conchoidal; fragments sharp-edged.

Colour bronze yellow, steel-gray, sometimes brownish or tarnished; streak shining; hard; brittle.

Physical Char.—By rubbing gives out a sulphurous odour, and, according to some, the smell of arsenic.

Constituent Parts.—According to some mineralogists this variety is composed of sulphur and iron, with a portion of arsenic.

Localities, &c.—The first variety is universally diffused; it is found in every kind of rock, and often in great abundance.

The second is rarer; but is not uncommon in veins of lead and silver, and sometimes in nests in indurated marl. It is found in Saxony and Bohemia, in Derbyshire. This variety is more subject than the first to decomposition.

Capillary pyrites is only found in small quantity, as in Saxony, and Andreaesberg in the Hartz.

Hepatic pyrites is only found in veins, particularly those of silver and lead, accompanied with quartz, calcareous spar, and heavy spar, as in Germany and Siberia, and at Wanlockhead in Scotland.

Exposed to the air, this variety is extremely liable to decomposition.

3. Species. MAGNETIC PYRITES.

Id. Kirwan, ii. 79. Id. Brochant, ii. 232.

Exter. Char.—Massive or disseminated; internal lustre shining or weakly shining; fracture uneven, rarely conchoidal; fragments rather sharp-edged.

Colour between copper red and bronze yellow; when exposed to the air it becomes brownish or tarnished; hard, or semihard; brittle. Spec. grav. 4.51.

Phys. Char.—This variety of pyrites acts on the magnetic needle, but not very powerfully.

Chem. Char.—Before the blow-pipe it gives out a slight odour of sulphur, and melts easily into a grayish black globule, which is attracted by the magnet.

| Constituent Parts. | Hatchett. | |-------------------|----------| | Iron | 63.5 | | Sulphur | 36.5 | | | 100.0 |

Localities, &c.—Magnetic pyrites has been only found in primitive rocks, as in micaceous schistus; and is usually disposed in beds, along with other ores of iron, and accompanied by quartz, hornblende, and garnets. It is found in Saxony, Bavaria, Bohemia, and in Caernarvonshire in Wales.

Uses.—This, as well as the former species, is employed for the purpose of extracting sulphur, or of manufacturing copperas, or sulphate of iron.

4. Species. MAGNETIC IRON ORE.

Magnetic Ironstone, Kirwan, ii. 158. Id. Brochant, ii. 235. Fer Oxidulé, Hauy, iv. 10.

This is divided into two subspecies, common and arenaceous.

Subspecies 1. COMMON MAGNETIC IRON ORE.

Exter. Char.—Massive or disseminated, and often also crystallized in six-sided prisms, having a three-sided pyramid at each extremity, set on three alternate lateral edges; an oblique four-sided prism; a double four-sided pyramid, or perfect octahedron, which is sometimes truncated on all its edges. Crystals of various sizes; faces sometimes smooth; those of the four-sided prism streaked transversely; lustre shining; internal lustre resplendent, or weakly glimmering; fracture uneven, sometimes conchoidal or foliated; fragments rather blunt-edged.

Colour iron-black, perfect black, or steel-gray; streak brownish black; semihard, or hard; brittle; more or less easily frangible. Spec. grav. 4.2 to 4.93.

Subspecies 2. ARENAEOUS MAGNETIC IRON ORE.

Exter. Char.—Found in rounded grains, from the size of millet to that of a nut, and sometimes in small octahedral crystals; external surface rough or weakly glimmering; internal shining or refulgent; fracture conchoidal; fragments sharp-edged.

Colour deep iron black, sometimes ash gray.

Phys. Char.—Magnetic iron ore, as the name imports, strongly attracts the magnetic needle, and iron filings; to the compact varieties of this ore, in which this property was first discovered, the name of natural magnet is given.

Chem. Char.—Magnetic iron ore becomes brown before the blow pipe, and colours borax dark green.

Constituent Parts.—This is supposed to be an oxide of iron in considerable purity, as it yields from 80 to 90 per cent. of metallic iron.

Localities, &c.—Common magnetic iron ore is very common in primitive mountains, particularly in those of gneiss and micaceous schistus, where it forms very powerful beds, and even entire mountains. It is disseminated in crystals in chlorite schistus, as in Corsica, and in basalt and greenstone, at Taberg in Sweden. Found in Saxony, Bohemia, and Italy, and particularly in the island of Elba in the Mediterranean; and indeed is very universally distributed over every part of the globe.

The second variety, or magnetic sand, is found in the beds of rivers, in a loose state, and sometimes imbedded in basalt and wacken. It is found in those countries where the other ores of iron abound; and also in the sand of many of the rivers within the torrid zone, as in Jamaica, St Domingo, &c.

Uses.—Magnetic iron is wrought for the purpose of obtaining metallic iron. Most of the Swedish iron ores belong to this variety, and furnish the iron which is so celebrated on account of its superior qualities, throughout Europe.

Magnetic sand, where it is abundant, is also smelted as an iron ore.

5. Species. SPECULAR IRON ORE.

Id. Broch. ii. 242. Id. Kirw. ii. 162. Micaceous Iron Ore, ibid. 284. Fer Oligifile, Hauy, iv. 38.

This species is divided into two subspecies, common and micaceous.

Subspecies 1. COMMON SPECULAR IRON ORE.

Exter. Char.—Massive or disseminated, but most frequently crystallized in doubled three-sided pyramids; flattened, and the lateral faces of the one set on the lateral edges of the other; the same pyramid with the angles at the common base truncated; in perfect cubes, having the angles truncated; or the cube considered as a double three-sided pyramid; or as a rhomboid, in which the summits are furmouted by an obtuse three-sided pyramid, set on the lateral faces; the same cube bevelled at each of the angles of the common base; in six-sided tables variously modified, or in perfect lenses. Surface of the crystals smooth, resplendent; internal lustre weakly shining or resplendent; fracture uneven, sometimes conchoidal or foliated; fragments sharp-edged.

Colour steel-gray, bluish, or reddish; sometimes with tarnished colours, which are iridescent; streak dark cherry-red; hard; opaque; brittle. Spec. grav. 4.79 to 5.21.

Chem. Char.—Before the blow-pipe it is infusible; but heated on charcoal becomes white, and melts with borax into a dirty yellow flag.

Phys. Char.—Affects the magnetic needle, but does not attract iron filings.

Constituent Parts.—This variety is supposed to be a pretty pure oxide of iron, yielding from 60 to 80 per cent. of iron.

Of this subspecies two varieties have been formed, compact and foliated, depending probably on the appearance of the fracture.

Subspecies 2. Micaceous Iron Ore.

Exter. Char.—Massive or disseminated, or in thin six-sided tables, so grouped together as to appear cellular; surface smooth, resplendent; internal lustre resplendent; fracture foliated; fragments in tables.

Colour iron-black, steel-gray, or dark red; in thin plates slightly translucent; streak dark cherry-red; semifluid; brittle. Spec. grav. 4.5 to 5.

Localities, &c.—These varieties are found in primitive mountains, in beds or veins, accompanied by other ores of iron, and in such quantity in many places as to be dug out for the purpose of manufacture, as in Germany, France, Russia, Sweden, Siberia, and particularly in the islands of Corsica and Elba, which furnish the finest specimens of specular iron ore for the cabinet.

The latter variety is found in England, and some parts of Scotland.

6. Species. Red Iron Ore.

This is divided into four subspecies; 1. red iron froth; 2. compact; 3. red haematites; and, 4. red ochre.

Subspecies 1. Red Iron Froth.

Id. Broch. ii. 249. Red Scaly Iron Ore, Kirw. ii. 172.

Exter. Char.—Sometimes massive, and frequently superficial; lustre glimmering or shining, usually composed of scaly friable particles which stain strongly; feels greasy.

Colour dark cherry-red, blood-red, brownish-red, or steel-gray.

Chem. Char.—Blackens before the blow-pipe.

Constituent Parts. Hauy.

| Iron | 66 | | Oxgen | 28.5 | | Silica | 4.25 | | Alumina | 1.25 |

100.00*

Localities, &c.—A rare mineral, usually incrusting other ores of iron. Found in Germany, and in Cornwall and at Ulverstone in Lancashire in England.

Vol. XIV. Part I.

Subspecies 2. Compact Red Iron Ore.

Id. Broch. ii. 251. Id. Kirw. ii. 170.

Exter. Char.—Massive or disseminated, in imitative forms, as cellular, &c., or crystallized in perfect cubes, or four-sided pyramids with truncated summits. Surfaces of the cube smooth; that of the pyramids rough and dull; internal lustre glimmering; fracture even, sometimes uneven or conchoidal; fragments rather blunt-edged.

Colour brownish-red, dark steel-gray, sometimes blood-red; semifluid; brittle; streak blood-red; stains. Spec. grav. 3.4 to 3.8.

Chem. Char.—Infusible before the blow-pipe.

Constituent Parts. Lampadius.

| Oxide of iron | 65.4 | | Silica | 20.7 | | Alumina | 9.3 | | Oxide of manganese | 2.7 | | Lofs | 1.9 |

100.0

Localities, &c.—Found along with other iron ores, abundant in Cumberland and Lancashire, and various places of the world.

Subspecies 3. Red Haematites.

Id. Kirw. ii. 168. Id. Broch. ii. 254.

Exter. Char.—Massive, and in various imitative forms; surface smooth or druffy; internal lustre shining, or only glimmering; fracture fibrous; fragments wedge-shaped.

Colour brownish-red, steel-gray, or blood-red; streak light blood-red; hard or semifluid; brittle; stains. Spec. grav. 4.7 to 5.

Constituent Parts.—It yields from 60 to 70 per cent. of iron, and contains, it is supposed, a portion of alumina, silica, and manganese.

Localities, &c.—This ore of iron is not very common, although in some places it is very abundant, as in the west of England. It is disposed in veins and beds, accompanied by the former variety.

Subspecies 4. Red Ochre.

Id. Kirw. ii. 171. Id. Broch. ii. 256.

Exter. Char.—Found massive, disseminated, or superficial; dull; fracture earthy.

Colour between blood-red and brownish-red; stains much; soft; often friable.

Localities, &c.—This variety usually accompanies the former, and is a very fusible iron ore.

7. Species. Brown Iron Ore.

This is divided into four subspecies; 1. brown iron froth; 2. compact; 3. brown haematites; and, 4. brown ochre.

Subspecies 1. Brown Iron Froth.

Brown Scaly Iron Ore, Kirw. ii. 166. Le Eisenrahmbraun, Broch. ii. 258. Metallic Ores.

Exter. Char.—Massive or disseminated, often superficial, or spumiform; strongly glimmering or shining; fracture foliated or compact.

Colour between brown and dull gray; very soft; almost friable; stains; feels greasy; nearly swins on water.

Chem. Char.—Blackens before the blow-pipe without fusion.

Localities, &c.—Accompanies other iron ores, as in Saxony, but is rare.

Subspecies 2. Compact Brown Iron Ore.

Exter. Char.—Massive or disseminated, sometimes in different imitative forms; dull, or rarely glimmering; fracture smooth, earthy, or conchoidal.

Colour clove brown, or brownish yellow; streak yellowish brown; semihard; brittle. Spec. grav. 3.07 to 3.75.

Localities, &c.—In veins or beds, accompanied by other iron ores, in various parts of the world.

Subspecies 3. Brown Hematites.

Id. Kirw. ii. 163. Id. Broch. ii. 261.

Exter. Char.—Massive, but most frequently in different imitative forms; surface smooth, granulated, rough or drusy; lustre thinning; internal lustre glimmering or weakly shining; fracture fibrous; fragments splintery, or wedge-shaped.

Colour clove brown, blackish brown, sometimes yellow, and sometimes with tarnished colours; opaque; streak yellowish brown; semihard; brittle. Spec. grav. 3.78 to 4.02.

Localities, &c.—Always accompanies the preceding variety, but in smaller quantity.

Subspecies 4. Brown Ochre.

Id. Kirw. ii. 167. Id. Broch. ii. 263.

Exter. Char.—Massive or disseminated; dull; fracture earthy; fragments blunt-ended.

Colour yellowish brown, or ochre yellow; soft; sometimes friable; stains more or less.

Localities, &c.—Always accompanies compact brown iron ore, and is therefore found in similar places.

8. Species. Sparry Iron Ore.

Id. Brochant, ii. 264. Id. Kirw. ii. 190.

Exter. Char.—Massive, disseminated, sometimes with impressions, and often crystallized. Its forms are, the rhomboid with plane or convex faces, or having two opposite angles strongly truncated; and the lens, the equiangular six-sided prism, or the simple or double four-sided pyramid. Crystals small; surface smooth, sometimes drusy, sometimes a little rough; lustre thinning and somewhat metallic; internal lustre thinning, rarely resplendent, between pearly and vitreous; fracture foliated; fragments rhomboidal.

Colour yellowish gray, grayish white, and exposed to the air, blackish brown, or with tarnished colours; sometimes translucent at the edges; those of a dark colour, opaque; semihard, or soft; brittle. Spec. grav. 3.6 to 4.

Chem. Char.—Before the blow-pipe it blackens without fusion.

Constituent Parts.—According to Bergman, this mineral contains equal parts of carbonate of lime and of iron, with about one-fourth of manganese.

Localities, &c.—Found equally in primitive and stratiform rocks, and always accompanied by calcareous spar, and other ores of iron, as in Saxony, France, Britain, and Ireland.

9. Species. Black Iron Ore.

Id. Kirw. ii. 167. Id. Broch. ii. 268.

This species is divided into two subspecies: 1. compact; and 2. black hematites.

Subspecies 1. Compact Black Iron Ore.

Exter. Char.—Massive, or in various imitative forms; surface rough or dull; internal lustre glimmering; fracture flat conchoidal; fragments sharp-edged.

Colour between steel gray and bluish-black; semi-hard; brittle.

Subspecies 2. Black Hematites.

Exter. Char.—Massive or kidney-form; internal lustre glimmering and shining; fracture fibrous, sometimes even; fragments wedge-shaped.

Colour steel gray.

Constituent Parts.—This ore is supposed to contain a larger proportion of manganese, with alumina and lime, than other ores of iron.

Localities, &c.—Found in veins in primitive mountains, and sometimes also in stratiform mountains, accompanied by brown and sparry iron ore.

10. Species. Argillaceous Iron Stone.

This is divided into six subspecies: 1. red chalk; 2. columnar argillaceous iron stone; 3. granular; 4. common; 5. reniform; and, 6. piliform.

Subspecies 1. Red Chalk.

Id. Broch. ii. 271.

Exter. Char.—Massive; fracture slaty; lustre glimmering; cross fracture earthy, dull; fragments in plates, or splintery.

Colour brownish red, black or blood red; streak blood red; writes and stains; soft; adheres to the tongue; feels meagre. Spec. grav. 3.13 to 3.93.

Chem. Char.—Decrepitates, and becomes black when exposed to a red heat.

Localities, &c.—Usually accompanies clay slate, either in thin beds, or in masses, as at Thalitter in Hesse, where it is dug out in considerable quantity. It is also found in Bohemia and Saxony.

Uses.—Employed as crayons in drawing, and for this purpose it is dug out, rather than as an ore of iron.

Red chalk, on account of the quantity of alumina and other earths which it contains, was formerly arranged in the argillaceous genus. Subspecies 2. Columnar Iron Stone.

*Id. Kirw. ii. 176.* *Id. Broch. ii. 273.*

**Exter. Char.**—Found in angular or rounded pieces; surface rough and dull; fracture dull and earthy; composed of columnar distinct concretions, which are often a little curved, sometimes straight and articulated, and very easily separated; surface of the concretions rough and dull.

Colour cherry red, blood or brownish red; streak blood red, sometimes yellowish brown; soft; adheres to the tongue; feels meagre, and is a little rough.

**Localities, &c.**—Usually met with in beds of clay, in stratiform mountains, and particularly in the neighbourhood of subterranean fires, by the effects of which, as it is supposed, it may have been produced. It is found in Bohemia and some other places, where it is wrought as an ore of iron.

Subspecies 3. Granular Iron Stone.

*Id. Broch. ii. 274.* *Acinoe Iron Ore, Kirw. ii. 177.*

**Exter. Char.**—Massive, or constituting the base of petrifications; strongly glimmering or weakly shining; fracture uneven, sometimes flat; fragments blunt-edged.

Colour reddish and yellowish brown, or grayish black; streak blood red, or varying according to the colour of the ore, usually soft or semihard. Specific gravity 2.673.

**Constituent Parts.** Lampadius.

| Oxide of iron | 64 | | Alumina | 23 | | Silica | 7.5 | | Water | 5 | | Lofs | .5 |

100.0

**Localities, &c.**—Is found only in stratiform mountains, as in Bohemia, Bavaria, and Switzerland.

Subspecies 4. Common Iron Stone.

*Id. Kirw. ii. 173.* *Id. Broch. ii. 276.*

**Exter. Char.**—Massive or disseminated, sometimes cellular or botryoidal; dull; fracture earthy; fragments rather sharp-edged.

Colour yellowish or bluish gray; yellowish brown, or brownish red; streak varies with the colour; soft; brittle; adheres to the tongue; feels meagre.

**Localities, &c.**—A common ore of iron in many places of Saxony and Bohemia, in Norway, and in England. It is connected with stratiform mountains, alternating with beds of clay slate.

Subspecies 5. Reniform Iron Stone.

*Id. Broch. ii. 278.* *Nodular Iron Ore, Kirw. ii 178.*

**Exter. Char.**—Found in rounded or tuberculated pieces, of a kidney-form figure; surface rough, covered with earthy particles; internal lustre glimmering; fracture smooth or earthy; fragments rather sharp-edged; composed of lamellar and concentric distinct concretions, including a nodule which is usually moveable.

Colour yellowish brown; streak the same; soft; brittle; adheres to the tongue; feels meagre. Specific gravity 2.57.

**Localities, &c.**—Found in Bohemia, Saxony, Silesia, and Poland, and in the coal countries of England and Scotland, and almost always in clay beds, sometimes accompanied with bituminous wood, in stratiform mountains.

This variety was formerly called *atites* or *eagle-stone*, as it was supposed that the eagle carried it to its nest.

Subspecies 6. Pisiform Iron Stone.

*Id. Kirw. ii. 178.* *Id. Broch. ii. 280.*

**Exter. Char.**—In spherical or flattened particles, which are generally small; surface rough, dull; internal lustre glimmering or weakly shining; fracture smooth.

Colour between brown and red; streak yellowish-brown; semihard; brittle. Spec. grav. 5.2.

**Constituent Parts.** Vanquelin.

| Iron | 30 | | Oxygen | 18 | | Alumina | 31 | | Silica | 15 | | Water | 6 |

100

**Localities, &c.**—This variety is found in considerable beds in stratiform mountains. It is abundant in France, Switzerland, and some parts of Germany.

II. Species. Bog Iron Ore.

This is divided into three subspecies: 1. morassy; 2. swampy; and 3. meadow.

Subspecies 1. Morassy Bog Iron Ore.

*Id. Kirw. ii. 183.* *Id. Broch. ii. 283.*

**Exter. Char.**—Sometimes earthy, sometimes in amorphous, tuberculated, or corroded masses; fracture earthy.

Colour yellowish-brown; stains; soft; friable; feels meagre.

Subspecies 2. Swampy Iron Ore.

*Id. Kirw. ii. 183.*

**Exter. Char.**—In amorphous masses, which are tuberculated or corroded; dull or slightly glimmering; fracture earthy; fragments blunt-edged.

Colour dark yellowish-brown, blackish brown, or steel-gray; streak light yellowish brown; very soft; brittle; heavier than the former.

Subspecies 3. Meadow Iron Ore.

*Id. Kirw. ii. 182.* *Id. Broch. ii. 284.*

**Exter. Char.**—In kidney-form, tubercled, often corroded masses; externally dull or rough; internal lustre shining, resinous; fracture conchoidal, or earthy when it is dull; fragments rather blunt-edged.

Colour dark blackish-brown, or yellowish-brown; streak yellowish-brown; soft and brittle.

**Constituent Parts.**—Bog iron ore is an oxide of iron, combined with the phosphate of iron, with some earthy matters, as alumina and silica. Localities, &c.—Bog iron ore is more abundant in the northern than in the southern parts of Europe. It is not uncommon in Poland, Prussia, Sweden, and in the Western islands of Scotland, as Jura and Islay. It is sometimes found in extensive beds, alternating with sandstone and clay.

12. Species. Blue Earthy Ore.

Id. Broch. ii. 288. Blue Martial Earth, Kirw. ii. 185.

Native Prussianate of Iron, of others.

Exter. Char.—Usually found slightly cohering, or loose, or friable; particles dull; stains, and feels meagre.

Colour grayish-white, indigo blue, rarely smalt-blue.

Chem. Char.—Becomes reddish-brown before the blow-pipe; melts into a black globule; easily soluble in acids.

Constituent Parts.—It was suspected by Bergman, that this was a native Prussian blue; but according to Klaproth, it is composed of iron and phosphoric acid, with a mixture of alumina.

Localities, &c.—Found in small nests in beds of clay, or bog iron ore, as in Saxony, Russia, and Siberia.

13. Species. Green Earthy Iron Ore.

Green Martial Earth, Kirw. ii. 188.

Exter. Char.—Found friable and superficial, rarely massive; internally dull; fracture earthy.

Colour yellowish or olive-green; stains; soft; feels meagre.

Chem. Char.—Becomes red before the blow pipe, and then dark-brown, but without fusion.

Constituent Parts.—It is conjectured to be a compound similar to the former, but in different proportions.

Localities, &c.—Found in Saxony, in veins, and accompanied with quartz and pyrites.

14. Species. Phosphate of Iron.

Id. Jour. de Physique, lviii. 259. Ann. de Chim. i. 200.

Exter. Char.—Found in rounded pieces, composed of capillary crystals, which seem to be four-sided prisms; fracture radiated and divergent.

Colour blue, from a blue powder coating the crystals, which are otherwise colourless; semitransparent. Spec. grav. 2.5 to 2.6.

Constituent Parts.

| Oxide of iron | Cadet. | Laugier. | |--------------|-------|---------| | Phosphoric acid | 42.1 | 41.25 | | Silica | 3. | 1.25 | | Alumina | 5.8 | 5. | | Lime | 9.1 | - | | Water | 13.1 | 31.25 | | Lofs | - | 2. |

Localities, &c.—This mineral is found imbedded in clay in the isle of France, and in Brazil.

15. Species. Pitchy Iron Ore, or Phosphate of Iron and Manganese.

Id. Broch. ii. 533. Jour. de Mines, N° 64. p. 295.

Exter. Char.—Massive; surface earthy and dull; internal lustre weakly shining, resinous; fracture compact or foliated.

Colour dark reddish-brown, or black; opaque; semifluid; brittle; streak dark red. Spec. grav. 3.956.

Chem. Char.—Melts before the blow-pipe into a black enamel.

Constituent Parts. Vauquelin.

| Oxide of iron | 31 | | Oxide of manganese | 42 | | Phosphoric acid | 27 |

Localities, &c.—Found near Limoges.

16. Species. Cube Ore, or Arseniate of Iron.

Id. Phil. Trans. 1801. p. 190.

Exter. Char.—Found crystallized in small cubes, grouped together in a drusy form; crystals sometimes truncated on their angles; surface smooth, shining; lustre between resinous and adamantine; fracture conchoideal.

Colour olive-green, yellow, or brown; translucent; semifluid; powder yellow. Spec. grav. 3.

Chem. Char.—Before the blow-pipe froths up with the smell of arsenic, and melts into a yellowish-gray metallic globule.

Constituent Parts.

| Oxide of iron | Vauquelin. | Chenevix. | |--------------|-----------|-----------| | Oxide of copper | 48 | 45.5 | | Arsenic acid | 18 | 31 | | Silica | - | 4 | | Lime | 2 | - | | Water | 32 | 10.5 |

Localities, &c.—Found in the copper mines in Cornwall.

17. Species. Arseniate of Iron and Copper.

Id. Phil. Trans. 1801. p. 219.

Exter. Char.—Crystallized in four-sided rhomboidal prisms, with two edges very obtuse, and two very acute, terminated by an acute four-sided pyramid; edges of the prism are sometimes truncated.

Colour bluish white; crystals semitransparent; semifluid. Spec. grav. 3.4.

Constituent Parts.

| Oxide of iron | 27.5 | | Oxide of copper | 22.5 | | Arsenic acid | 33.5 | | Silica | 3 | | Water | 12 | | Lofs | 1.5 |

Localities, Localities, &c.—Found in Cornwall, in Siberia, and Spain.

18. Species. Chromate of Iron.

Id. Broch. ii. 534. Id. Hauy, iv. 129.

Exter. Char.—Massive; glimmering or weakly shining; fracture compact and uneven, or imperfectly foliated.

Colour grayish or blackish brown; opaque; streak ash-gray; smell earthy when breathed on; hard. Spec. grav. 4.032.

Chem. Char.—Infusible before the blow-pipe; melts with borax, and colours it of a beautiful green.

| Constituent Parts | |------------------| | Oxide of iron, | 35 | | Chromic acid, | 43 | | Alumina, | 20 | | Silica, | 2 | | | 100 |

Localities, &c.—Discovered by Pontier in France, in the department of Var, and found in considerable abundance in veins and nodules, in beds of serpentine; found also in Siberia.

VII. LEAD Genus.

1. Species. Galena.

This is divided into two subspecies; common and compact galena.

Subspecies 1. Common Galena.

Id. Kirw. ii. 216. Id. Broch. ii. 294. Plomb Sulfure, Hauy, iii. 456.

Exter. Char.—Massive, disseminated, superficial, in imitative forms, or crystallized in cubes, octahedrons, six-sided prisms, and six-sided tables; all which are variously modified by truncations and bevelments on the edges and angles. Crystals grouped or imbedded; surface smooth, or drusy; lustre from glimmering to resplendent; internal the same; fracture foliated; fragments cubic, excepting the fine-grained galena.

Colour lead gray, sometimes tarnished, or iridescent; soft; easily frangible; stains a little. Spec. grav. 7.22 to 7.38.

Chem. Char.—Decrepitates before the blow-pipe, and fuses, giving out a sulphureous odour.

Constituent Parts.—Composed of sulphur and lead in variable proportions, and generally a little silver, sometimes antimony. The proportion of lead is from 50 to 80 per cent.

Localities, &c.—This is the most common ore of lead, and exists in all kinds of rocks, either in beds or veins. In many countries this lead ore is dug out to a great extent, as in Germany, France, and Britain.

Subspecies 2. Compact Galena.

Id. Kirw. ii. 218. Id. Broch. ii. 301.

Exter. Char.—Massive, disseminated, kidney-form, or peculiar; lustre of the specular variety resplendent; the others only glimmering; internal lustre glimmering; fracture even or conchoidal; fragments rather sharp-edged.

Colour lead or steel-gray; streak shining; stains; soft. Spec. grav. 7.44.

Localities, &c.—This is a rare mineral. It is found along with common galena, in Saxony, and other parts of Germany; in Derbyshire, where it is known by the name of flickenfside, and in the county of Durham, where it is known by the name of looking-glass ore.

2. Species. Blue Lead Ore.

Id. Kirw. ii. 220. Id. Broch. ii. 203.

Exter. Char.—Rarely massive, most commonly crystallized in regular six-sided prisms, which are often a little curved, and sometimes fascicularly grouped; surface rough; longitudinally streaked; lustre glimmering; fracture even.

Colour between lead-gray and indigo blue; opaque; streak shining; soft, easily frangible. Specific gravity 5.46.

Chem. Char.—Melts easily before the blow pipe; burns with a bluish flame, and a sulphureous odour, leaving a globule of lead.

Its constituent parts have not been exactly ascertained. Supposed to be a green lead ore, which has undergone some change, but retaining its original form.

Localities, &c.—This ore has only been found in Saxony, and also, it is said, in France and Hungary.

3. Species. Brown Lead Ore.

Id. Kirw. ii. 222. Id. Broch. ii. 305.

Exter. Char.—Rarely massive, commonly crystallized in equal six-sided prisms, or the crystals are acicular or capillary; lustre glimmering; internal shining; fracture uneven.

Colour reddish or clove-brown; translucent at the edges; streak white; soft; brittle. Spec. grav. 6.6 to 6.97.

Chem. Char.—No effervescence with acids; fuses readily before the blow-pipe, but is not reduced; crystallizes in small needles on cooling.

| Constituent Parts | |------------------| | Oxide of lead, | 78.58 | | Phosphoric acid, | 19.73 | | Muriatic acid, | 1.65 | | Loss, | .04 | | | 100.00|

Localities, &c.—Found along with white lead ore, quartz, and heavy spar, in France and Germany.

4. Species. Black Lead Ore.

Id. Kirw. ii. 221. Id. Broch. ii. 307.

Exter. Char.—Massive, disseminated, cellular, but most frequently crystallized in six-sided prisms, with equal or unequal sides, or bevelled at the extremity. Crystals small, irregularly grouped; smooth, and sometimes longitudinally streaked; lustre shining; fracture uneven.

Colour Colour grayish black; opaque; streak grayish black; soft; brittle. Spec. grav. 5.7.

Chem. Char.—Decrepitates before the blow-pipe; and is then reduced to the metallic state.

Constituent Parts. Lampadius.

Oxide of lead, 78.5 Carbonic acid, 18 Carbone, 1.5 Water, 2

100.0

Localities, &c.—Found in Saxony, England, and Scotland, frequently accompanying white lead ore.

5. Species. White Lead Ore, or Carbonate of Lead.

Id. Kirw. ii. 203. Id. Broch. ii. 309. Plomb Carbonaté, Hauy, iii. 475.

Exter. Char.—Rarely massive, commonly disseminated, superficial, or crystallized in six-sided prisms; in four-sided prisms; in double crystals, composed of two four-sided prisms; in oblique four-sided prisms, and in double six-sided pyramids. These are variously modified by truncations and acuminations on the edges and angles. They are also of various sizes, and variously grouped together; surface usually smooth, resplendent, sometimes rough or streaked; lustre thinning, adamantine; fragments conchoidal, splintery, or fibrous.

Colour white, yellowish, or grayish white; transparent or translucent; refraction double. Specific gravity 6.48 to 7.23.

Chem. Char.—Decrepitates before the blow-pipe, becomes yellowish or reddish, and melts into a metallic globule; effervesces strongly with acids.

Constituent Parts.

Klaproth. Macquart.

Oxide of lead, 82 73 Carbonic acid, 16 24 Water, 2 3

100 100

Some carbonates of lead are also combined with a small portion of iron and earthy matters.

Localities, &c.—Found in veins, accompanied by galena and other lead ores, in Germany, France, and Britain.

6. Species. Green Lead Ore, or Phosphate of Lead.

Plomb Phosphate, Hauy, iii. 490. Id. Broch. ii. 314. Phosphorated Lead Ore, Kirw. ii. 207.

Exter. Char.—Massive or disseminated, botryoidal or reniform, and often crystallized in six-sided prisms, truncated on all the edges, or on the terminal edges, or terminated by a six-sided pyramid; in five-sided prisms with the lateral faces converging towards one of the extremities; and in six-sided pyramids; but this last is rare. Surface smooth, shining; internal lustre weakly shining and refrinous; fracture uneven.

Colour olive green, emerald green, yellow or brown; grayish, greenish, or yellowish white; transparent, or only at the edges; streak greenish white; brittle. Spec. grav. 6.909 to 6.941.

Chem. Char.—Melts easily before the blow-pipe, into a grayish polyhedral globule, but without being reduced; soluble in acids, without effervescence, but sometimes with difficulty.

Constituent Parts. Klaproth.

Oxide of lead, 77.10 80 Phosphoric acid, 19 18 Muriatic acid, 1.54 1.62 Oxide of iron, .10 — Loft, 2.26 .38

100.00 100.00

Localities, &c.—Found in veins along with other lead ores, and generally near the top of the vein, in Germany, France, and Leadhills in Scotland.

7. Species. Red Lead Ore, or Chromate of Lead.

Id. Broch. ii. 318. Red Lead Spar, Kirw. ii. 214.

Exter. Char.—Rarely massive, sometimes disseminated or superficial, but most frequently crystallized in oblique four-sided prisms with the extremity bevelled, or the lateral edges truncated; and in six-sided prisms, with two broad and two narrow faces; lateral faces longitudinally streaked; external surface smooth, thinning; fracture even.

Colour aurora red, or hyacinth red; translucent or semiflattiransparent; streak orange yellow; soft; brittle. Spec. grav. 5.75 to 6.02.

Chem. Char.—No effervescence with acids; decrepitates a little before the blow-pipe, and melts into a black flag.

Constituent Parts. Vauquelin.

Oxide of lead, 64 Chromic acid, 36

100

Localities, &c.—Found in veins at Berezof in Siberia, accompanied by other ores of lead, some ores of iron, and native gold.

A similar ore of lead, but of a brown colour, was brought from Mexico by Humboldt.

8. Species. Yellow Lead Ore, or Molybdate of Lead.

Id. Broch. ii. 322. Yellow Lead Spar, Kirw. ii. 212. Hauy, iii. 498.

Exter. Char.—Rarely massive, usually crystallized in rectangular four-sided tables; in perfect cubes, with plane or convex faces, or truncated on the terminal edges; in four-sided tables bevelled on the terminal faces, in obtuse octahedrons, truncated on the summit, the lateral angles, or lateral edges. Crystals small; surface smooth and shining; internally shining; lustre waxy; fracture conchoidal.

Colour wax yellow, or honey yellow; translucent, or only at the edges; soft; brittle. Spec. grav. 5.48 to 5.7. Chem. Char.—Before the blow-pipe it decrepitates strongly, and then melts into a blackish-gray globule, in which are seen particles of lead. Soluble in nitric acid, and in fixed alkalies.

**Constituent Parts.**

| | Macquart | Hatchett | |----------------|----------|----------| | Oxide of lead | 63.5 | 58.4 | | Molybdic acid | 28 | 38 | | Oxide of iron | | 2.1 | | Silica | 4 | .28 | | Carbonate of lime | 4.5 | | | Lofs | | 1.22 |

100.0 100.00

Localities, &c.—This ore of lead was first discovered at Bleyberg in Carinthia; it has been since found in Saxony and France.

9. Species. NATIVE SULPHATE OF LEAD.

Id. Kirw. ii. 211. Broch. ii. 325. Hauy, iii. 503.

Exter. Char.—Crystallized in irregular octahedrons, which are variously truncated and bevelled. Crystals smooth and shining; lustre shining and vitreous; fracture compact.

Colour snow white, grayish or yellowish white; translucent; semihard. Spec. grav. 6.3.

Chem. Char.—Reduced even in the flame of a candle; insoluble in nitric acid.

**Constituent Parts. Klaproth.**

| | | |----------------|----------| | Oxide of lead | 70.5 | | Sulphuric acid | 25.75 | | Water | 2.25 | | Lofs | 1.5 |

100.00

Localities, &c.—Found on brown iron ore in the island of Anglesea, and on galena in the veins at Leadhills and Wanlockhead in Scotland.

10. Species. EARTHY LEAD ORE.

Id. Broch. ii. 327. Id. Kirwan, ii. 105.

This is divided into two subspecies: 1. friable; and, 2. indurated.

Subspecies 1. Friable Lead Ore.

Exter. Char.—This is composed of fine earthy particles, which are dull, and have little coherence.

Colour sulphur or ochre yellow, yellowish or smoke gray; stains; feels meagre.

Subspecies 2. Indurated Lead Ore.

Exter. Char.—Massive or disseminated; dull; fracture uneven or earthy.

Colour of the former; opaque; streak lighter colour; very soft and friable.

Chem. Char.—Easily reduced before the blow-pipe, into a black flag; effervesces a little with acids.

Constituent Parts.—Earthy lead ore is supposed to be a mixture of oxides of lead, with a little oxide of iron, and some earthy matters.

Localities, &c.—Found on the surface, or in the cavities of other lead ores, in Saxony, France, Siberia, and at Leadhills and Wanlockhead in Scotland.

II. Species. MURIATE OF LEAD.

Exter. Char.—Massive, or crystallized in cubes, or flat six-sided prisms; external surface shining; internal lustre resplendent, adamantine; fracture foliated.

Colour between asparagus green and wine yellow; semitransparent; soft; not brittle; streak dull, white.

**Constituent Parts. Klaproth.**

| | | |----------------|----------| | Oxide of lead | 55 | | Muriatic acid | 45 |

100

Localities, &c.—Found in Derbyshire, and also, it is said, in the mountains of Bavaria, but not crystallized.

12. Species. MURIO-CARBONATE OF LEAD.

Id. Bournon and Chenevix, Nich. Jour. 4to. p. 219.

Exter. Char.—Crystallized in cubes, which are variously modified; lustre shining, adamantine; fracture foliated; crofs fracture conchohoidal.

Colour straw yellow, or clear white; semitransparent; streak dull, snow white; easily scratched by carbonate of lead. Spec. grav. 6.065.

**Constituent Parts. Chenevix.**

| | | |----------------|----------| | Oxide of lead | 51 | | Muriate of lead| 59 | | Oxide of lead | 34 | | Carbonate of lead | 40 | | Lofs | 1 |

100 100

Localities, &c.—Found in Derbyshire.

13. Species. ARSENATE OF LEAD.

Id. Broch. ii. 546.

Exter. Char.—Disseminated sometimes in an earthy state, sometimes in silky filaments, and crystallized in small, double, six-sided pyramids. Dull, or weakly glimmering; lustre silky.

Colour citron or greenish yellow; very soft; friable.

Chem. Char.—Before the blow-pipe it melts easily into a globule of lead, and gives out the smell of garlic.

Constit. Parts.—Composed of oxide of lead and of arsenic, with some oxide of iron and earthy matters.

VIII. TIN GENUS.

1. Species. TIN PYRITES.

Id. Kirw. ii. 200. Id. Broch. ii. 332.

Exter. Char.—Found massive or disseminated; lustre shining

Metallic Ores.

Shining or weakly shining; fracture uneven; fragments rather blunt-edged.

Colour steel gray, sometimes brass or bronze yellow; semifluid; brittle. Spec. grav. 4.3 to 4.7.

Chem. Char.—Before the blow-pipe it melts easily into a black flag, but without being reduced, and gives out a sulphurous smell.

Constituent Parts. Klaproth.

| Tin | Copper | Iron | Sulphur | Earthy substances | |-----|--------|------|---------|------------------| | 34 | 36 | 3 | 25 | 2 |

100

Localities, &c.—This is a rare mineral, found only in Cornwall, in a vein along with copper pyrites.

2. Species. COMMON TINSTONE, or Oxide of Tin.

Id. Kirw. ii. 197. Id. Broch. ii. 334. Hauy, iv. 137.

Exter. Char.—Massive, disseminated, in rounded pieces or grains, and often crystallized in rectangular four-sided prisms, which are variously modified by truncations and bevelments; in octahedrons, which are rare; in eight-sided prisms, or in double octahedrons, which are united by one of their summits as to form a re-entering angle. Crystals of various sizes, always grouped together; surface smooth; lustre shining or resplendent; internal lustre shining, between vitreous and resinous; fracture uneven.

Colour brownish black, blackish brown, yellowish gray, or grayish white; opaque, or semitransparent; streak light gray; hard; brittle. Specific gravity 6.3 to 6.9.

Chem. Char.—Before the blow-pipe it decrepitates, loses its colour, and is partially reduced to the metallic state.

Constituent Parts. Klaproth.

| Tin | Iron | Oxygen | Silica | |-----|------|--------|-------| | 77.5| .25 | 21.5 | .75 |

100.00

Localities, &c.—Found in Germany, in the East Indies, and particularly in Cornwall in England. It is not very universally distributed; but where it exists, it is deposed in granite, gneiss, micaceous schistus, and porphyry; and either in masses, veins, or disseminated in the rocks.

3. Species. GRAINED TIN ORE, or Wood Tin.

Id. Broch. ii. 340. Id. Kirw. ii. 298.

Exter. Char.—Found only in small pieces, rounded or angular; surface rough; weakly shining; internal lustre glimmering; a little silky; fracture fibrous; fragments wedge-shaped.

Colour hair brown of various shades; streak yellowish gray; hard and brittle. Spec. grav. 5.8 to 6.4.

Chem. Char.—Becomes brownish red before the blow-pipe, then decrepitates strongly, but is infusible.

Confl. Parts.—According to Klaproth, it is composed of 63 of tin in the 100, with a little iron and arsenic.

Localities, &c.—Found in Cornwall, in alluvial land, where it seems to have been deposed in a stalactitical form, accompanied by common tin.

IX. BISMUTH GENUS.

1. Species. NATIVE BISMUTH.

Id. Kirw. ii. 264. Id. Broch. ii. 343. Id. Hauy, iv. 184.

Exter. Char.—Rarely massive, but usually disseminated in a plumose or reticulated form, and rarely crystalized, in small four-sided tables or cubes; lustre shining or resplendent; fracture foliated.

Colour silvery white, inclining to red; colours commonly tarnished; soft; almost ductile. Specific gravity 9.02 to 9.82.

Chem. Char.—Fusible almost in the flame of a candle; by increasing the heat it is volatilized; soluble with effervescence in nitric acid, and precipitated by water in the form of a white powder.

Localities, &c.—Bismuth is a rare metal, found in veins in primitive mountains, accompanied by calcareous spar, heavy spar, and quartz, and commonly with gray cobalt, sometimes also with black blend and native silver. Found in Saxony, Bohemia, France, and Sweden.

2. Species. VITREOUS BISMUTH ORE.

Sulphurated Bismuth, Kirwan, ii. 266. Id. Brochant, ii. 346.

Exter. Char.—Massive or disseminated; rarely crystallized in small imbedded capillary prisms; lustre shining or resplendent; fracture radiated or foliated.

Colour between lead gray and tin white; stains a little; soft; easily frangible. Specific gravity 6.13 to 6.46.

Chem. Char.—Easily fusible before the blow-pipe, with a sulphurous odour.

Confl. Parts.—Composed of bismuth about 60 per cent. and sulphur with a little iron.

Localities, &c.—Found in Bohemia, Saxony, and Sweden, and is usually accompanied by native bismuth.

3. Species. OCHRE OF BISMUTH.

Id. Kirwan, ii. 265. Id. Brochant, ii. 348.

Exter. Char.—Rarely massive, commonly disseminated on the surface of other minerals; internally glimmering; fracture uneven or earthy.

Colour yellowish gray, ash gray, or straw yellow, opaque; soft; sometimes even friable. Spec. grav. 4.37.

Chem. Char.—Very easily reduced before the blow-pipe to the metallic state; effervesces with acids. Localities, &c.—This mineral is very rare, and chiefly found near Schneeberg in Saxony, along with native bismuth; and also in Bohemia and Swabia.

X. ZINC GENUS.

1. Species. BLENDE.

Id. Brochant, ii. 350. Id. Kirwan, ii. 237. Zinc Sulfure, Hauy, iv. 167.

This species is divided into three subspecies; yellow, brown, and black.

Subspecies 1. YELLOW BLENDE.

Exter. Char.—Massive or disseminated, or sometimes crystallized in cubes or octahedrons, but they are so confused as to prevent the form being easily discovered. Surface smooth, resplendent; internal lustre resplendent, between adamantine and vitreous; fracture foliated; cleavage six-fold; fragments rather sharp-edged, or affume sometimes a dodecahedral form, which is the result of the complete cleavage.

Colour dark sulphur yellow, olive green, or brownish red; translucent, sometimes semitransparent; streak yellowish gray; semi-hard; brittle. Spec. grav. 4.04 to 4.16.

Chem. Char.—Decrepitates before the blow-pipe, and becomes gray, but is infusible.

Constituent Parts. Bergman.

| Zinc | 64 | | Sulphur | 20 | | Iron | 5 | | Fluoric acid | 4 | | Water | 6 | | Silica | 1 |

Physical Char.—Most of the varieties of yellow blende become phosphorescent by friction in the dark.

Localities, &c.—Found in Saxony, Bohemia, Hungary and Norway, accompanied by lead, copper, and iron ores. It is rather a rare mineral.

Subspecies 2. BROWN BLENDE.

Exter. Char.—Massive, disseminated, and sometimes crystallized in simple three-sided pyramids, octahedrons, and four-sided prisms, which are variously modified. External lustre shining or resplendent; surface sometimes druly; internal lustre shining, between vitreous and resinous; fracture foliated; cleavage six-fold.

Colour reddish, or yellowish brown; colour sometimes tarnished; translucent, or opaque; crystals trans-

Localities, &c.—Very common in veins of lead ore, in most parts of the world.

Subspecies 3. BLACK BLENDE.

Exter. Char.—Massive, or disseminated, or crystalized like the former, which it resembles in most of its characters.

Colour perfect black, brownish black, or blood red; often iridescent.

Constituent Parts. Bergman.

| Zinc | 45 | | Sulphur | 29 | | Iron | 9 | | Lead | 6 | | Silica | 4 | | Water | 6 | | Arsenic | 3 |

Localities, &c.—Found in the same places with the former.

2. Species. CALAMINE.

This is divided into two subspecies, compact and foliated.

Subspecies 1. COMPACT CALAMINE.

Id. Kirwan, ii. 234. Id. Brochant, ii. 361.

Exter. Char.—Massive or disseminated, cellular, or stalactitical; dull; fracture compact or earthy.

Colour grayish white, yellowish, or reddish, or milk white; opaque; semi-hard or friable; brittle; stains sometimes. Spec. grav. 3.52, to 4.1.

Chem. Char.—Decrepitates before the blow-pipe when suddenly heated; is infusible. Forms a jelly with acids, and sometimes effervesces.

Constituent Parts.

| Oxide of zinc | 84 | | Silica | 12 | | Iron | 3 | | Alumina | 1 | | Water | 4.4 | | Lofs | 2.3 |

Localities, &c.—Metallic Ores. Another variety examined by the same chemist contained,

| Oxide of zinc | 71.4 | |--------------|-----| | Carbonic acid | 13.5 | | Water | 15.1 |

100.0

From these analyses it appears, that calamines are very different in their composition, consisting sometimes of oxide of zinc, silica, and water, and this variety forms a jelly with acids; others are composed of carbonic acid and oxide of zinc, which effervesce in sulphuric acid, but do not form a jelly; a third variety is composed of oxide of zinc, carbonic acid, and water, constituting a hydro-carbonate of zinc, which is soluble with effervescence in sulphuric acid.

Localities, &c.—Usually accompanied with iron ochre, and very often with galena, white lead, and other metallic ores. Found in Bohemia, Bavaria, France, and Britain, in some places in considerable abundance.

Subspecies 2. FOLIATED CALAMINE.

Id. Brochant, ii. 364. Kirwan, ii. 236. Hauy, iv. 161.

Exter. Char.—Found massive or disseminated, flaky, lamellated, incrusted, or crystallized, in small four-sided tables, or in very small cubes with plane or convex faces, shining, or glimmering; lustre between pearly and vitreous; fracture radiated.

Colour yellowish, or smoke gray; grayish, or yellowish white; translucent or semitransparent; semi-hard; brittle. Specific gravity 3.52.

Chem. Char.—Becomes white before the blow-pipe, but is infusible, and does not effervesce with acids.

Phys. Char.—Becomes electric by heat.

Localities, &c.—This variety accompanies the former, lining its cavities, but is less common. It is found in the same places.

XI. ANTIMONY GENUS.

1. Species. NATIVE ANTIMONY.

Id. Brochant, ii. 369. Id. Kirwan, ii. 245. Id. Hauy, iv. 252.

Exter. Char.—Found massive, disseminated, or reniform; resplendent; fracture foliated.

Colour tin white; but exposed to the air, grayish or yellowish; soft; easily frangible. Spec. grav. 6.7.

Chem. Char.—Before the blow-pipe it is very easily fusible into a metallic globule, which gives out fumes with the odour of garlic.

Confl. Parts.—Native antimony sometimes contains a small proportion of arsenic.

Localities, &c.—Has only been found in two places: at Sahlberg in Sweden, where it was discovered in 1748, in limestone; and at Allemont in France, where it is accompanied by other ores of antimony and cobalt.

2. Species. GRAY ORE OF ANTIMONY.

Id. Brochant, ii. 371. Kirwan, ii. 246. Hauy, iv. 64.

This is divided into four subspecies; compact, foliated, radiated, and plumose.

Subspecies 1. COMPACT GRAY ORE OF ANTIMONY.

Exter. Char.—Massive or disseminated; shining; fracture uneven.

Colour lead gray, or steel gray; soft; not very brittle; stains a little; streak shining. Spec. grav. 4.36.

Localities, &c.—This variety is rarer than the others, but is met with in Saxony, Hungary, and France.

Subspecies 2. FOLIATED ORE OF ANTIMONY.

Exter. Char.—Massive or disseminated; fracture foliated. In other characters it resembles the other varieties, and is usually accompanied by the following.

Subspecies 3. RADIATED ORE OF ANTIMONY.

Exter. Char.—Massive, disseminated, and very often crystallized in acicular, often in capillary crystals, and in fixed and four-sided prisms variously modified; surface streaked longitudinally; internal lustre refulgent; fracture radiated, straight, parallel, or divergent.

Colour similar to the preceding; soft; not very brittle. Spec. grav. 4.1 to 4.5.

Constituent Parts. Bergman.

Antimony, 74 Sulphur, 26

100

Localities, &c.—This is the most common ore of antimony, and is found in Germany, France, and Sweden. There is only one mine of antimony in Britain, which is in the south of Scotland, near Westerhall, in the neighbourhood of Langholm.

Subspecies 4. PLUMOSE ORE OF ANTIMONY.

Exter. Char.—Usually found in capillary crystals, so interwoven, that they form a superficial covering to other minerals; these groups are externally weakly shining; internal lustre glimmering; fracture fibrous.

Colour similar to the former, and sometimes tarnished brown or like tempered steel; opaque; soft; sometimes almost friable; brittle.

Confl. Parts.—Plumose antimony is composed of sulphuret of antimony combined with arsenic, iron, and accidentally a little silver.

Chem. Char.—Before the blow-pipe this and the other varieties of gray antimony give out white fumes, with a sulphurous smell, and are almost entirely volatilized, or changed into a black flag.

Localities, &c.—Plumose antimony is found at Freyberg in Saxony, in the Hartz, and in Hungary.

3. Species. 3. Species. Black Ore of Antimony.

Exter. Char.—Found crystallized in rectangular four-sided tables, truncated on the edges or angles; crystals smooth; lustre shining; fracture conchoidal.

Colour iron black; soft.

Localities, &c.—This species, which is also a sulphuret of antimony, combined probably with some other ingredients, is found in Cornwall.

4. Species. Red Ore of Antimony.

Id. Kirwan, ii. 250. Id. Brochant, ii. 379. Antimoine Hydroaulfuré, iv. 276.

Exter. Char.—Massive or disseminated, but most commonly in capillary crystals; lustre weakly shining, vitreous; fracture fibrous.

Colour cherry red, brown, reddish, or bluish; soft, almost friable; brittle. Specific gravity 3.7 to 4.

Chem. Char.—Before the blow-pipe it melts easily, and in nitric acid a white powder is deposited.

Constituent Parts. Klaproth.

| Oxide of antimony | 78.3 | | Sulphur | 19.7 | | Lofs | 2 |

100.0

Localities, &c.—Found in Saxony and France, usually accompanying gray or native antimony.

5. Species. White Ore of Antimony.

Muriated Antimony, Kirwan, ii. 151. Antimoine Oxidé, Hauy, iv. 273.

Exter. Char.—Rarely massive, usually superficial, in divergent fibres, or crystallized in rectangular four-sided tables, cubes, or four-sided prisms. Crystals aggregated; smooth; streaked longitudinally; resplendent; internal lustre shining, between adamantine and pearly; fracture foliated.

Colour snow white, yellowish white, or grayish; translucent; soft; brittle.

Chem. Char.—Crystals decrepitate before the blow-pipe, but in powder is easily fusible.

Confl. Parts.—Was formerly supposed to be a muriate of antimony, but according to Klaproth, it is a pure oxide. The white ore of France, according to Vaquelin, contains,

| Oxide of antimony | 86 | | Lead | 3 | | Silica | 8 | | Lofs | 3 |

100

6. Species. Ochre of Antimony.

Id. Brochant, ii. 383. Id. Kirwan, ii. 252.

Exter. Char.—Massive, disseminated, or in superficial crusts, on gray antimony; dull; fracture earthy.

Colour straw yellow, or yellowish gray; soft; friable.

Chem. Char.—Infusible before the blow-pipe; becomes white, and emits white fumes. Its constituents are unknown.

Localities, &c.—In Saxony and Hungary, accompanying gray and red antimony, and in the antimony mine near Weiterhall, in the south of Scotland.

II. Cobalt Genus.

1. Species. White Cobalt Ore.

Id. Kirw. ii. 382. Id. Broch. ii. 386.

Exter. Char.—Massive, disseminated, reniform, and rarely crystallized in small four-sided tables, or in small cubes or octahedrons. Lustre weakly shining, or shining; fracture uneven.

Colour tin white, but on the surface variable, and tarnished; streak shining; hard; brittle.

Chem. Char.—Easily fusible before the blow-pipe, emitting a dense vapour, with a smell of arsenic, and leaves a white metallic globule; colours borax-blue.

Localities, &c.—Found in Norway, Sweden, and Saxony, in beds of micaceous schists, along with red cobalt ore, quartz, and hornblende. Its composition is not known, but supposed to be alloyed with some other metals.

2. Species. Gray Cobalt Ore.

Id. Kirw. ii. 271. Id. Broch. ii. 388.

Exter. Char.—Massive, disseminated, reniform, and botryoidal; lustre shining; fracture even.

Colour light steel gray, or tin white; surface steel tarnished; streak shining; semi-hard; brittle.

Chem. Char.—Infusible before the blow-pipe; emitting fumes and the smell of arsenic.

Constituent Parts. Klaproth.

| Cobalt | 20 | | Arsenic| 33 | | Iron | 24 | | Lofs | 23 |

100

It contains also sometimes nickel and silver.

Localities, &c.—Found in Saxony, France, Norway, and Cornwall in England, with other ores of cobalt.

3. Species. Shining Cobalt Ore.

Id. Broch. ii. 390. Kirw. ii. 273.

Exter. Char.—Massive, disseminated, superficial, in various imitative forms, and crystallized in cubes and octahedrons, which are variously modified; crystals small, smooth, and resplendent, rarely drusy; lustre shining; fracture uneven, radiated, or fibrous.

Colour tin white, commonly grayish, or yellowish tarnished; hard; brittle. Spec. grav. 6.3 to 6.4.

Chem. Char.—Before the blow-pipe it burns with a small white flame, and a white vapour, smelling strongly of garlic; then blackens, and is almost infusible; soluble in nitric acid.

Constituent Parts of crystallized shining cobalt from Tunaberg in Sweden.

| Klaproth. | Taffaert. | |-----------|-----------| | Cobalt | 44 | 36.66 | | Arsenic | 55.5 | 49 | | Sulphur | 5 | 6.5 | | Iron | | 5.66 | | Lofs | | 2.18 |

100.0 100.00

H h 2 Localities, Localitys, &c.—This is the most common ore of cobalt; and it is usually accompanied by the other ores, and sometimes also by vitreous, red, and native silver. It is found in Bohemia, Saxony, Sweden, and Cornwall in England, and usually in beds in primitive mountains.

Uses.—This ore of cobalt is commonly wrought for the purpose of employing it in the preparation of the fine blue colour known by the name of smalt, which is used in the manufacture of porcelain, glaze, and as a pigment.

4. Species. Black Cobalt Ochre.

Id. Broch. ii. 396. Kirw. ii. 275. Hauy, iv. 214.

This is divided into two subspecies, friable and indurated.

Subspecies 1. Friable Cobalt Ochre.

Exter. Char.—Composed of particles which are more or less cohering; stains a little.

Colour brownish, bluish, or grayish black; streak thinning; feels meagre. In other characters it agrees with the following.

Subspecies 2. Indurated Cobalt Ochre.

Exter. Char.—Massive, disseminated, in imitative forms, or marked with impressions; dull, or weakly glimmering; fracture earthy.

Colour bluish black; streak shining, resinous; soft; semifluid; rather brittle. Spec. grav. 2.01 to 2.42.

Chem. Char.—Before the blow-pipe it gives out an arsenical odour, but is infusible.

Its constituent parts are supposed to be oxide of cobalt, with some iron and arsenic.

Localities, &c.—Both varieties are found together, and accompanied by ores of silver, copper, iron, in Saxony, Suabia, and the Tyrol, as well as in France and Spain.

5. Species. Brown Cobalt Ochre.

Id. Broch. ii. 400.

Exter. Char.—Massive, or disseminated; always dull; fracture earthy; streak thinning, resinous.

Colour light or dark liver brown; soft, almost friable; very easily frangible.

Constituent Parts.—Supposed to be composed of oxide of cobalt and iron.

Localities, &c.—Found at Saalfeld in Thuringia, in stratiform mountains, and in Würtemberg, in primitive mountains, accompanied by other varieties of cobalt ochre.

6. Species. Yellow Cobalt Ochre.

Id. Kirw. ii. 277. Broch. ii. 401.

Exter. Char.—Massive, or disseminated, or adhering to the surfaces of other minerals; dull; fracture earthy; streak shining, resinous.

Colour dirty straw yellow, or yellowish gray; very soft or friable.

Chem. Char.—Before the blow-pipe it gives out an odour of arsenic, and is infusible.

Its constituents are supposed to be oxide of cobalt, and a little arsenic.

Localities, &c.—Found in the same places with the former, but is rare.

7. Species. Red Cobalt Ochre, or Arseniate of Cobalt.

Id. Kirw. ii. 278. Broch. ii. Cobalt Arseniate, Hauy, iv. 216.

This is divided into two subspecies; earthy and radiated.

Subspecies 1. Earthy Red Cobalt Ochre.

Exter. Char.—In thin superficial layers, or crusts; dull, or weakly glimmering; fracture earthy.

Colour a peach-blossom red, rose red, or reddish white; streak a little shining; very soft, friable.

Localities, &c.—Found in Bohemia, Saxony, France, and Norway.

Subspecies 2. Radiated Red Cobalt Ochre, or Cobalt Bloom, or Flowers of Cobalt.

Exter. Char.—Massive, or disseminated, rarely botryoidal or reniform; often superficial, and in small drusy crystals, whose forms are rectangular four-sided tables, four-sided prisms, double fixed-angled pyramids, with different modifications. Crystals small and variously aggregated; smooth and shining, sometimes resplendent; fracture radiated; fragments wedge-shaped, or splintery.

Colour peach blossom red, crimson red, or, exposed to the air, brownish, grayish, or whitish; translucent; crystals semitransparent; soft; brittle.

Chem. Char.—Before the blow-pipe becomes blackish gray, giving out a feeble odour of arsenic, without any fumes, but is infusible. Colours borax a fine blue.

This species has not been particularly analyzed, but is considered as a compound of cobalt and arsenic acid.

Localities, &c.—The same as the former, and also in Cornwall in England, and along with copper ores at Alva in Scotland.

8. Species. Sulphate of Cobalt.

A saline substance in a stalactitical form, of a pale rose red colour and translucent, is found at Herrngrund near Newlohl in Hungary, which was at first supposed to be a sulphate of manganese, and afterwards a sulphate of cobalt.

This substance has been examined by Klaproth, who dissolved it in water, added an alkali, and obtained a bluish precipitate, which coloured borax of a beautiful sapphire blue; and with muriatic acid he obtained from it a sympathetic ink.

XIII. NICKEL Genus:

1. Species. Copper-coloured Nickel.

Id. Brochant, ii. 408. Sulphurated Nickel, Kirw. ii. 286. Nickel Arsenical, Hauy, iii. 518. Kupfernickel of the Germans.

Exter. Char.—Massive or disseminated, rarely reticulated; Mineralogy.

Classified; shining, or weakly shining; fracture uneven, sometimes conchoidal; fragments rather sharp-edged.

Colour pale copper red, whitish, or grayish; semihard; brittle. Spec. grav. 6.64 to 7.6.

Chem. Char.—Before the blow-pipe it gives out the fumes and odour of arsenic; melts with difficulty into a flag, mixed with metallic particles. Solution in acids, green.

Constituent Parts. Sage.

| Nickel | 73 | | Arsenic | 22 | | Sulphur | 2 | | Lofs | 1 |

Localities, &c.—Found in veins, in primitive and stratiform mountains, almost always accompanied with ores of cobalt, and often with rich silver ores. It is found in Bohemia, Saxony, France, Spain, and Cornwall in England.

2. Species. Nickel Ochre, or Oxide of Nickel.

Id. Kirw. ii. 283. Broch. ii. 411. Hauy, iii. 516.

Exter. Char.—Usually disseminated and efflorescent on other minerals; composed of friable, loose, and slightly agglutinated particles.

Colour apple-green of different shades; stains; feels meagre.

Chem. Char.—Remains unchanged before the blow-pipe; colours borax yellowish red, and is insoluble in nitric acid.

Constituent Parts. Lampadius.

| Oxide of nickel | 67 | | Iron | 23.2 | | Water | 1.5 | | Lofs | 8.3 |

Localities, &c.—Found in similar situations with the preceding species.

XIV. MANGANESE GENUS.

1. Species. Gray Ore of Manganese, or Oxide of Manganese.

Id. Brochant, ii. 414. Id. Kirwan, ii. 291. Id. Hauy, iv. 243.

This species is divided into four subspecies: 1. radiated; 2. foliated; 3. compact; and, 4. earthy.

Subspecies 1. Radiated Gray Ore of Manganese.

Eff. Char.—Colours borax violet.

Exter. Char.—Massive or disseminated, or crystallized in oblique four-sided prisms, or in acicular prisms fascicularly grouped together; the crystals are variously modified. Faces streaked longitudinally; shining or resplendent; fracture radiated; fragments wedge-shaped.

Colour steel gray, or iron black; streak black, without lustre; stains; soft; brittle. Specific gravity 3.7 to 4.7.

Constituent Parts. Cordier and Beaunier.

| From France | Germany | Piedmont. No. lviii. | |-------------|---------|---------------------| | Oxide of manganese | 83.5 | 82. | 86. | | Brown oxide of iron | 2. | - | 3. | | Carbonate of lime | - | 7.5 | - | | Barytes | 1.5 | 3. | - | | Silica | 7.5 | 7. | 5. | | Lofs | 5.5 | 5. | 4.5 |

Of purer specimens by Klaproth.

| Oxide of manganese | 99.25 | 92.75 | | Water | .25 | 7. | | Lofs | .5 | .25 |

Subspecies 2. Foliated Gray Ore of Manganese.

Exter. Char.—Found massive, disseminated, or crystallized in small, rectangular, four-sided tables, fascicularly grouped; lustre shining; fracture foliated.

Colour similar to the former; streak black and dull; stains; soft, and brittle. Spec. grav. 3.74.

Subspecies 3. Compact Gray Ore of Manganese.

Exter. Char.—Massive or disseminated, in angular, or botryoidal, or dendritical forms; lustre glimmering; fracture uneven, sometimes even or conchoidal.

Colour steel gray, or bluish black; stains; semihard, or soft; brittle.

Confl. Parts—approach pretty nearly to those of the radiated variety.

Subspecies 4. Earthy Gray Ore of Manganese.

Exter. Char.—Found massive, disseminated, sometimes superficial and dendritical; dull; sometimes a little glimmering; fracture earthy.

Colour between steel gray and bluish black; stains very much; very soft, often even friable; feels meagre.

Constituent Parts—supposed to be the same as the former, but with a larger proportion of oxide of iron.

Chem. Char.—Gray ore of manganese is infusible before the blow-pipe, but becomes of a blackish brown colour; gives a blue colour to borax.

Localities, &c.—All the varieties of this species are usually found together, and chiefly in primitive mountains. The earthy ore of manganese almost always accompanies sparry iron ore, and other ores of iron. Manganese is found in considerable abundance in Saxony, Bohemia, France, near Exeter in England, and in Aberdeenshire in Scotland.

2. Species. Black Ore of Manganese.

Exter. Char.—Found massive, disseminated, or crystallized in small four-sided double pyramids, arranged Metallic Ores.

in rows; surface shining; internal lustre weakly glimmering; fracture imperfectly foliated.

Colour grayish black, and brownish black; streak dull, brownish red; soft; brittle.

Localities, &c.—This species is of rare occurrence. It has been found in Thuringia, forming a crust on gray ore of manganese, and also, it is said, in Piedmont.

3. Species. RED ORE OF MANGANESE, or Carbonate of Manganese.

Exter. Char.—Massive, disseminated, botryoidal, &c., or crystallized in flat rhomboids, or in very small pyramids or lenses. Surface of the crystals smooth; dull, or weakly glimmering; fracture uneven or splintery.

Colour rose red, or brownish white; translucent at the edges; semihard; brittle. Spec. grav. 3.23.

Chem. Char.—Infusible before the blow-pipe; becomes grayish black, and colours borax violet blue, or crimson red.

Constituent Parts. Lampadius.

| Oxide of manganese | 48 | |-------------------|----| | Iron | 21 | | Carbonic acid | 49 | | Silica | .9 |

Localities, &c.—This species of manganese, which is rare, is found in Transylvania at Offenbanya, and particularly at Nagyag, where it constitutes part of the mass of an auriferous vein, from which the gold ore of Nagyag is obtained.

XV. MOLYBDENA Genus.

1. Species. SULPHURET OF MOLYBDENA.

Id. Brochant, ii. 432. Id. Kirwan, ii. 322. Id. Hauy, iv. 289.

Exter. Char.—Massive or disseminated, sometimes in plates, and rarely crystallized in equal six-sided tables; crystals small, imbedded, the lateral faces shining; internal lustre shining; fracture foliated; fragments rather blunt-edged, sometimes in plates.

Colour lead gray; opaque; stains, and writes; very soft, and easily frangible; flexible in thin plates, but not elastic; feels greasy. Spec. grav. 4.56 to 4.73.

Chem. Char.—Infusible before the blow-pipe; gives out a sulphureous smell; nitric acid converts it to a white oxide, which is the molybdic acid.

Constituent Parts.

| Pelletier | Klaproth | |----------|----------| | Molybdic acid | 45 | 60 | | Sulphur | 55 | 40 |

Localities, &c.—Always found in primitive mountains, in nests or nodules, and very commonly in the neighbourhood of tin ores. It is also accompanied by wolfram, quartz, native arsenic, and fluor spar. It is found in Bohemia, Saxony, Sweden, France, and England.

XVI. ARSENIC Genus.

1. Species. NATIVE ARSENIC.

Id. Broch. ii. 435. Id. Kirw. ii. 255. Id. Hauy, iv. 220.

Exter. Char.—Massive, disseminated, in imitative forms, or with impressions; surface rough or granulated; dull, or weakly glimmering; internal lustre weakly shining; fracture uneven, sometimes imperfectly foliated; fragments rather blunt-edged in plates.

Colour light lead gray, tin-white or grayish black when tarnished; streak shining; semihard; very easily frangible. Spec. grav. 5.72 to 5.76.

Chem. Char.—Melts readily before the blow-pipe, giving out white vapour, with the smell of garlic; then burns with a bluish flame, and is dissipated, leaving only a whitish powder, which is the oxide of arsenic.

Constituent Parts.—Native arsenic is usually alloyed with a small portion of iron, and sometimes also with a little gold or silver.

Localities, &c.—Found in veins in primitive mountains, accompanied by ores of silver, lead, copper, quartz, and earthy spars, in Bohemia, Saxony, and France.

2. Species. ARSENICAL PYRITES.

Id. Broch. ii. 438. Id. Kirw. ii. 256. Fer Arsenical, Hauy, iv. 56.

This is divided into two subspecies, common and argentiferous.

Subspecies 1. COMMON ARSENICAL PYRITES.

Exter. Char.—Massive, disseminated, often crystallized in oblique four-sided prisms, acute octahedrons, and lenses; the prisms being variously modified on their angles, faces, and extremities. Crystals small; lateral faces smooth, shining; bevelled faces streaked transversely; lustre shining; fracture uneven.

Colour silvery white, but usually tarnished yellow, or bluish, and iridescent; hard; brittle. Specific gravity 5.75 to 6.52.

Phys. Char.—By friction gives out the odour of garlic.

Chem. Char.—Before the blow-pipe gives out a white vapour with the odour of arsenic, the fumes depositing a white powder on cold bodies; a reddish brown matter, which is infusible, remains.

Constituent Parts.—Composed of arsenic, iron, and sulphur.

Subspecies 2. ARGENTIFEROUS ARSENICAL PYRITES.

Exter. Char.—Rarely massive, often disseminated, and crystallized in small, acicular, four-sided prisms; lustre shining, or weakly shining; fracture uneven.

Colour tin-white, or silvery-white, usually tarnished.

Localities, &c.—Arsenical pyrites is found in Bohemia, Saxony, and Silexia, in veins of primitive mountains, or disseminated in the rocks.

The second variety is found in similar places, and differs only from the first, in being combined with a small quantity of silver, which varies from 1 to 10 per cent. 3. Species. Orpiment.

Id. Kirw. ii. 260. Id. Broch. ii. 444. Hauy, iv. 234.

This species is divided into two subspecies, yellow and red.

Subspecies 1. Yellow Orpiment.

Exter. Char.—Massive, disseminated, superficial, and crystallized in oblique four-sided prisms, bevelled at the extremity, or terminated by a four-sided pyramid, or in acute octahedrons. Crystals small, and confusedly aggregated; surface smooth; that of the bevelment and pyramids finely streaked; internal lustre resplendent, between resinous and adamantine; fracture foliated; fragments in plates.

Colour citron-yellow, golden-yellow, or aurora-red; translucent; in thin plates, semitransparent; soft; flexible in thin plates. Spec. grav. 3.31 to 3.45.

Chem. Char.—Gives out a blue flame before the blowpipe, with white vapour, and the smell of arsenic and sulphur.

Constituent Parts.

| Arsenic | Kirwan. | Westrumb. | |---------|---------|-----------| | Sulphur | 84 | 80 |

Localities, &c.—Usually found in stratiform mountains, accompanied by clay, quartz, and sometimes by red orpiment, in Transylvania, Hungary, and other places.

Subspecies 2. Red Orpiment.

Exter. Char.—Rarely massive, usually disseminated, or superficial, and often crystallized in oblique four-sided prisms, with obtuse lateral edges, truncated, or bevelled: crystals small, streaked longitudinally; thinning or resplendent; internal lustre shining between vitreous and resinous; fracture uneven, or conchoidal.

Colour light aurora-red, scarlet-red, orange yellow; translucent, or semitransparent, often opaque; streak orange, or citron-yellow; very soft; somewhat brittle. Spec. grav. 3.2.

Chem. Char.—Similar to the former.

Constituent Parts.—According to some, the same as the preceding, but with the addition of iron and silica, with a smaller proportion of sulphur.

Localities, &c.—Chiefly found in primitive mountains, as in Saxony, Hungary, France, and in the neighbourhood of Etna and Vesuvius.

4. Species. Native Oxide of Arsenic.

Id. Kirw. ii. 258. Id. Broch. ii. 450. Id. Hauy, iv. 225.

Exter. Char.—Found superficial, in an earthy form, and friable, on other minerals; rarely indurated, sometimes botryoidal, or crystallized in capillary crystals, very small octahedrons, or four-sided tables; lustre glimmering or dull; fracture earthy or fibrous.

Colour snow-white, yellowish white, reddish or greenish white; opaque; crystals translucent; soft, or friable. Spec. grav. 3.706.

Chem. Char.—Before the blow-pipe it gives out a white fume, and a garlic odour; burns with a bluish flame, and is entirely disfigured; soluble in water and acids.

Constituent Parts.—This is a pure oxid of arsenic, with an accidental mixture of earth.

Localities, &c.—A rare mineral, but is found in small quantity, along with native arsenic, and ores of cobalt, in Bohemia and Hungary.

5. Species. Pharmacolite, or Arseniate of Lime.

Id. Broch. ii. 523. Chaux Arseniée, Hauy, ii. 293.

Exter. Char.—Found in small capillary crystals; lustre glimmering, silky; fracture fibrous or radiated.

Colour snow-white; translucent; very soft. Specific gravity 2.53 to 2.64.

Chem. Char.—Soluble in nitric acid with effervescence, and gives out the odour of arsenic before the blow-pipe.

Constituent Parts. Klaproth.

| Arsenic acid | 50.54 | | Lime | 25 | | Water | 24.46 |

Localities, &c.—Found in a vein in primitive rocks, accompanied by heavy spar and gypsum, near Wittichen in Swabia. It has also been found in France.

XVII. TUNGSTEN GENUS.

1. Species. Wolfram.

Id. Kirw. ii. 316. Id. Broch. ii. 456. Scheelin Feruginé, Hauy, iv. 314.

Exter. Char.—Found massive, disseminated, or crystallized in six-sided prisms, and in rectangular four-sided tables, which are variously modified. Crystals not very small, usually grouped; internal lustre thinning or resplendent; longitudinal fracture foliated; cross fracture uneven.

Colour brownish black, or perfect black, sometimes tarnished; opaque; streak dark reddish-brown; soft; brittle. Spec. grav. 7.11 to 7.33.

Chem. Char.—Before the blow-pipe it decrepitates, but is infusible.

Constituent Parts.

| Delhiuyart. Wiegleb. Klaproth. Vaquelin. | |------------------------------------------| | Tungstic acid | 65 | 35.75 | 46.9 | 67. | | Oxide of manganese | 22 | 32 | | 6.25 | | Oxide of iron | 13 | 11 | 31.2 | 18. | | Silica | | | | 1.5 | | Lofs | | 21.25 | 21.9 | 7.25 |

Localities, &c.—Wolfram, which is a rare mineral, is found in primitive mountains, accompanied by quartz, and 2. Species. Tungstate of Lime.

*Tungsten*, Kirw. ii. 314. *Id.* Broch. ii. 453. *Scheelin Calcaire*, Hauy, iv. 320.

*Exter. Char.*—Massive, disseminated, sometimes crystallized in regular octahedrons, which are sometimes slightly bevelled on the edges of the common base. Crystals usually small; surface smooth, resplendent; bevelled surface streaked transversely; internal lustre shining or resplendent, resinous or adamantine; fracture foliated.

Colour grayish or yellowish white; translucent; semi-hard; brittle. Spec. grav. 6.06.

*Chem. Char.*—Before the blow-pipe decrepitates, and loses its transparency, but is infusible. Reduced to powder, and digested with nitric or muriatic acid, it leaves a citron yellow residuum, which is tungstic acid.

**Constituent Parts.** Klaproth.

| Oxide of tungsten | 77.75 | 75.25 | |-------------------|-------|-------| | Iron | | 1.25 | | Manganese | | .75 | | Lime | 17.6 | 18.7 | | Silica | 3 | 1.5 | | Loss | 1.65 | 2.55 |

100.00 100.00

*Localities,* &c.—This is a rare mineral, usually found in primitive mountains, accompanied by ores of tin, some iron ores, quartz, fluor spar, &c. in Sweden, Saxony, and Cornwall in England.

XVIII. TITANIUM Genus.

1. Species. Menachanite.

*Id.* Brochant, ii. 468. *Id.* Kirwan, ii. 326. *Hauy*, iv. 305.

*Exter. Char.*—Found in small, detached, rounded grains; surface rough, or weakly glimmering; lustre shining, semi-metallic; fracture imperfectly foliated.

Colour grayish or iron black; soft or semi-hard; brittle. Spec. grav. 4.4.

*Chem. Char.*—Infusible before the blow-pipe; colours borax greenish brown.

**Constituent Parts.**

| Chenevix. | Klaproth. | |-----------|-----------| | Oxide of titanium | 45.25 | 40 | | Iron | 51. | 49 | | Silica | 3.5 | 11 | | Oxide of manganese | 2.5 |

100.00 100

*Localities,* &c.—This mineral was first discovered by Mr Gregor, among sand, in the bed of a rivulet, in the valley of Menachan in Cornwall; hence its name. It has since been found in the island of Providence, one of the Bahamas, and at Botany Bay in New Holland.

2. Species. Octahedrite.

*Anatase*, Hauy, iii. 129. *Id.* Brochant, ii. 548. *Octahedrite*, Saussure, Voyages, § 1901.

*Exter. Char.*—Found only crystallized, in elongated octahedrons with square bases, and truncated, or acuminate; crystals small and imbedded; lateral faces streaked transversely; lustre resplendent, vitreous; fracture foliated.

Colour steel gray, sometimes light indigo blue; translucent; semi-hard; brittle. Spec. grav. 3.85.

*Chem. Char.*—Infusible before the blow-pipe, but melts with borax, which it colours green, and in cooling, crystallizes in needles.

*Confl. Parts.*—It is chiefly composed of oxide of titanium.

*Localities,* &c.—Has been found lining the cavities of a vein, accompanied by quartz and feldspar, in a primitive rock, in Dauphiné in France.

3. Species. Titanite.

*Id.* Kirwan, ii. 329. *Le Ruthile*, Brochant, ii. 470. *Titane Oxide*, Hauy, iv. 296. *Red Schorl* of many.

*Exter. Char.*—Found crystallized in oblique four-sided prisms, the lateral edges truncated; sometimes these crystals are double, being united obliquely; also in acicular and capillary crystals, imbedded and grouped together; surface longitudinally streaked, shining; internal lustre shining, adamantine; fracture foliated.

Colour blood-red or reddish brown; opaque, or translucent; hard; brittle. Spec. grav. 4.1 to 4.24.

*Chem. Char.*—Infusible before the blow-pipe, but loses its transparency, and becomes gray.

*Confl. Parts.*—Composed chiefly of oxide of titanium.

*Localities,* &c.—Found in Hungary, in gneiss, and imbedded in quartz. It has been found also in Switzerland, Spain, and France.

4. Species. Nigrine.

*Kirwan*, ii. 331. *Brochant*, ii. 474. *Hauy*, iv. 307.

*Exter. Char.*—Disseminated, sometimes amorphous, often crystallized in oblique four-sided prisms, variously modified by truncations and bevelments. Surface smooth; lustre shining, or resplendent, between resinous and vitreous; fracture foliated.

Colour dark brownish black, yellowish white or violet brown; opaque, or translucent; semi-hard. Spec. grav. 3.51 to 4.6.

*Chem. Char.*—Infusible before the blow-pipe.

**Constituent Parts.**

| Klaproth. | Ahlgaard. | |-----------|-----------| | Oxide of titanium | 33 | 38 | 74 | | Silica | 35 | 22 | 8 | | Lime | 32 | 20 | 18 |

100 100 100

*Localities,* &c.—Found in Bavaria, and at Arendal in Norway.

5. Species. 5. Species. Brown Ore of Titanium.

This species in its characters so nearly resembles the preceding, that it may be considered merely as a variety, as has been done by Brochant and Hauy.

6. Species. Iserine.

Id. Brochant, ii. 478.

Exter. Char.—Found in rounded or angular grains, having a rough and glimmering surface; internally shining; fracture conchoidal.

Colour iron black, or brownish; hard; brittle. Spec. grav. 4.5.

Chem. Char.—Melts before the blow-pipe into a dark brown flag.

Constituent Parts. Klaproth.

Oxide of titanium, 59.1 Iron, 30.1 Uranium, 10.2

Loss, .6

100.0

Localities, &c.—Found in the sand of a river in Bohemia, called Jizer, whence the name is derived.

XIX. URANIUM Genus.

1. Species. Pitchy Ore of Uranium.

Id. Brochant, ii. 460. Kirw. ii. 305. Hauy, iv. 280.

Exter. Char.—Massive, disseminated, sometimes cellular; shining or glimmering; fracture imperfectly conchoidal; fragments rather sharp-edged.

Colour velvet black, iron black, or bluish, sometimes steel-tarnished; streak black; opaque; semi-hard; brittle. Spec. grav. 6.5 to 7.5.

Chem. Char.—Insoluble before the blow-pipe; soluble in nitric acid.

Constituent Parts. Klaproth.

Uranium a little oxidated, 86.5 Sulphuret of lead, 6. Oxide of iron, 2.5 Silica, 5.

100.0

Localities, &c.—Found in Bohemia and Saxony, accompanying galena, copper pyrites, iron ochre, and some ores of silver and cobalt.

2. Species. Micaceous Uranite.

Id. Brochant, ii. 463. Kirwan, ii. 304.

Exter. Char.—Sometimes in thin layers, but often crystallized in rectangular four-sided tables; in cubes, and six-sided prisms variously modified. Crystals small, and grouped together; lustre shining, pearly; fracture foliated.

Vol. XIV. Part I.

Colour emerald or grass green of various shades, rarely wax yellow; translucent; streak greenish white; soft; not very brittle. Spec. grav. 3.12.

Chem. Char.—Soluble, without effervescence, in nitric acid, which it colours citron yellow.

Confl. Parts.—This species is an oxide of uranium, with a small portion of copper.

Localities, &c.—Found in Saxony, France, and Cornwall in England, accompanied by some ores of iron, sometimes by cobalt.

3. Species. Uranite Ochre.

Id. Broch. ii. 466. Id. Kirw. ii. 303.

Exter. Char.—Found massive, but usually disseminated, or superficial; is dull, or rarely shining; fracture earthy, or foliated; fragments blunt-edged.

Colour citron yellow, aurora red, or sulphur yellow; opaque; soft and friable; brittle; stains a little; feels meagre. Spec. grav. 3.15 to 3.24.

Constituent Parts.—Composed of oxide of uranium, with a portion of iron.

Localities, &c.—Found in similar places with the former.

XX. TELLURIUM Genus.

1. Species. Native Tellurium.

Id. Broch. ii. 480. Sylvanite, Kirw. ii. 324. Hauy, iv. 325.

Exter. Char.—Massive or disseminated; shining; fracture foliated.

Colour between tia and silvery white; soft; not very brittle. Spec. grav. 5.7 to 6.1.

Chem. Char.—Melts easily before the blow-pipe.

Constituent Parts. Klaproth.

Tellurium, 92.6 Iron, 7.2 Gold, .2

100.0

Localities, &c.—Has been only found at Fatzebay in Transylvania, where it exists in veins, in mountains of gray wacken and transition limestone. The ore is dug out for the purpose of extracting the gold.

It was called aurum paradoxum, and aurum problematicum, because its external appearance did not indicate that it contained gold.

2. Species. Graphic Ore of Tellurium.

Id. Broch. ii. 482. Hauy, iv. 327.

Exter. Char.—Massive, and crystallized in flat four or six-sided prisms, which are arranged in rows, exhibiting something of the appearance of written characters, and hence the name graphic ore. Surface smooth, shining; longitudinal fracture foliated and resplendent; cross fracture uneven.

Colour tin white, yellowish; or lead gray; soft and brittle. Spec. grav. 5.72.

Chem. Char.—Burns with a greenish flame before the blow-pipe. **MINERALOGY**

### Metallic Ores

#### Constituent Parts

| Mineral | Parts | |---------|-------| | Tellurium | 60 | | Gold | 30 | | Silver | 10 |

Total: 100

**Localities, &c.**—Has only been found at Offenbanya in Transylvania, in veins traversing porphyry and granular limestone accompanied by iron pyrites and copper ore. It is wrought for the sake of the gold.

#### 3. Species. Yellow Ore of Tellurium.

*Id. Broch. ii. 484.* Hauy, iv. 327.

**Exter. Char.**—Disseminated, and crystallized in small four-sided prisms; thinning, or weakly shining; fracture foliated; cros fracture uneven.

Colour silver white, brassy yellow, or gray.

**Chem. Char.**—Soluble in nitric acid.

#### Constituent Parts

| Mineral | Parts | |---------|-------| | Tellurium | 44.75 | | Gold | 26.75 | | Lead | 19.5 | | Silver | 8.5 | | Sulphur | .5 |

Total: 100.00

**Localities, &c.**—Found only at Nagyag in Transylvania.

#### 4. Species. Black or Foliated Ore of Tellurium.

*Id. Broch. ii. 486.* Hauy, iv. 327.

**Exter. Char.**—Found in plates, which are united into masses, or disseminated, rarely crystallized in six-sided tables; surface smooth, shining; external lustre resplendent; fracture foliated.

Colour between lead gray and iron black; stains; soft; flexible in thin plates. Spec. grav. 8.91.

**Chem. Char.**—Before the blow-pipe the sulphur and tellurium are dissipated in white fumes, and a metallic globule remains, surrounded by a black flag.

#### Constituent Parts

| Mineral | Parts | |---------|-------| | Tellurium | 33 | | Lead | 50 | | Gold | 8.5 | | Silver and copper | 1 | | Sulphur | 7.5 |

Total: 100.0

**Localities, &c.**—Found only in the same place with the preceding.

### XXI. CHROMIUM GENUS

#### 1. Species. Needle Ore of Chromium.

**Exter. Char.**—Found in small crystals, which are imbedded; lustre shining; fracture uneven or conchoideal.

**Constituent Parts.** Klaproth.

Colour steel gray, and usually covered with a greenish efflorescence; soft, or semifluid; not very brittle.

**Constituent Parts.**—This is supposed to be an alloy of chromium.

**Exter. Char. &c.**—Found in the gold mine of Rudnick near Schlangenberg in Swabia, in a matrix of white quartz, containing gold and galena.

#### 2. Species. Ochre of Chromium.

**Exter. Char.**—Massive, disseminated, and in thin plates; dull; fracture uneven or earthy.

Colour verdigris green, or yellowish; soft.

**Localities, &c.**—Found only in the same place, accompanying the former.

The chromates of lead and iron have been already described among the ores of those metals.

### XXII. COLUMBIUM GENUS

**Exter. Char.**—Massive; fracture uneven, or foliated; lustre shining.

Colour dark gray; opaque; not very hard; brittle.

Spec. grav. 5.918.

#### Constituent Parts

| Mineral | Parts | |---------|-------| | Oxide of columbium | 78 | | Iron | 21 | | Loss | 1 |

Total: 100

**Localities, &c.**—This mineral, of which the only specimen known is in the British Museum, was brought from Massachusetts in America; it was analyzed by Mr Hatchett, and found to contain a new metal, which he denominated columbium.

### XXIII. TANTALIUM GENUS

Two species of this mineral have been discovered; tantalite, and yttrio-tantalite.

#### 1. Species. Tantalite.

**Exter. Char.**—Crystallized in octahedrons; surface smooth; fracture compact.

Colour bluish gray, or black. Spec. grav. 7.95.

**Constituent Parts.**—Composed of tantalum, iron, and manganese.

**Localities, &c.**—Found in Finland, in globular pieces, in a vein of red feldspar, traversing a gneiss rock.

#### 2. Species. Yttrio-Tantalite.

**Exter. Char.**—Disseminated, in pieces of the size of a nut; fracture even; lustre metallic.

Colour dark gray; may be scratched with a knife; powder gray. Spec. grav. 5.15.

**Constituent Parts.**—Composed of iron, manganese, tantalum, and the new earth yttria.

**Localities, &c.**—Found at Ytterby in Sweden, in the same place with gadolinite.

These minerals were analyzed by Eckeberg, who discovered in them the new metal tantalum, which is now supposed to be the same with columbium.

### XXIV. XXIV. CERIUM GENUS.

1. Species. Cerite.

Exter, Char.—Found massive or disseminated; lustre weakly glimmering; fracture fine grained, even.

Colour pale rose red; opaque; powder grayish; scratches glass. Spec. grav. 4.5 to 4.9.

Chem. Char.—Insoluble before the blow-pipe, and does not colour borax.

Constituent Parts.

| Oxide of cerium | Vanquelin | Klaproth | |-----------------|-----------|----------| | Iron | 67 | 54.5 | | Silica | 17 | 34 | | Lime | .02 | 2 | | Water and carbonic acid | .12 | 5 | | Lofs | 15.84 | 2.5 |

Localities, &c.—This mineral has been found in the copper mine of Bafnaes, at Riddarhytta, in Sweden, accompanied by copper, molybdena, bismuth, mica, and hornblende.

The new metal contained in this mineral was discovered by Hisinger and Berzelius, chemists at Stockholm.

APPENDIX.

IX. YTTRIAN GENUS.

To follow Strontian Genus, p. 209.

Species. Gadolinite.

Id. Brochant, ii. 512. Id. Hauy, iii. 141.

EXPLANATION OF THE PLATES.

Plate CCCLI.

Fig. 1. Represents the goniometer or graphometer, an instrument invented by Carangeau for measuring the angles of crystals. MTN is a graduated semicircle of brass or silver, furnished with two arms or rulers AB, FG, one of which, FG, has a slit from a to R, excepting the cross bar at K, which strengthens the instrument. This arm is fixed to a brass ruler at R and c placed behind, and which makes part of the semicircle. The arm FG is connected with the ruler behind by nails which enter the slit and are furnished with nuts. The other arm has also a slit or opening from x to e, where it is fixed to the first by the screw nail which passes through both. By slackening the screws, the two parts c G and c B may be shortened at pleasure. The arm AB being only fixed at c, which is the centre of the circle, moves round this centre, while the arm GF remains constantly fixed in the direction of the diameter which passes through the points o and 180°. The upper part of the arm AB should be brought to a thin edge from x to q, and the line of this edge should pass through the centre c; because it is by this edge that the measure of the angle on the graduated circumference is indicated.

To discover the measure of any angle of a crystal, the two arms c B, c G are brought into contact with the sides containing the angle, and the degree indicated by the line x s on the circumference denotes the measure of that angle. The instrument is so contrived that the arms may be shortened for the convenience of applying it in different cases. But it might happen that it could not be applied in cases where the crystals are aggregated or attached to the matrix. This difficulty is obviated by another contrivance. The semicircle is furnished with a hinge at 90°, by which means it may be diminished at pleasure to a quadrant, by folding back one half. There is a small bar of steel, one end of which is fixed behind the immovable arm FG, and the other is attached by a notch and screw nail at O. When this nail is unscrewed, the bar c O falls behind the ruler which supports FG, and thus one half of the semicircle folds back, and any angle not exceeding 90° may be measured; but when the angle is greater, it must be replaced.

Fig. 2. is an apparatus by which small degrees of electricity electricity may be observed in minerals. A is a small brass needle with knobs \(a\) \(b\), and moveable on the pivot at the middle. The mineral whose electricity is to be tried, is rubbed on silk or woollen, and then presented to one of the knobs; and by the distance at which the knob begins to be attracted, the strength of the electricity may be, in some degree, estimated. In the same way substances which become electric by heat, such as the tourmaline, are to be tried; the same apparatus may be employed. To ascertain in what part of the mineral the different electricities exist, take a stick of sealing wax, at the extremity of which a silk thread has been attached, and having rubbed the wax, bring alternately the opposite extremities of the substance, for example, each of the summits of a tourmaline, within a small distance of the silk thread. If the extremity which is brought near the thread possesses negative electricity, the thread will be repelled; on the contrary, it will be attracted. Or the experiment may be made in another way, particularly when the electrical body is small, or its electricity feeble. At B, fig. 2, the tourmaline \(t'\) is held by a pair of pincers in such a way that the pole \(i\) is at a small distance from the knob \(a\) of the needle. C \(c\) is the stick of wax, one of whose extremities is placed on a tube of glass \(U\) \(u\), and which acts by its extremity \(C\), on the knob \(a\), to excite in it positive electricity. In this case the wax, after the extremity which has been rubbed is placed in the position described, communicates to the knob of the needle to which it is presented, an electricity contrary to its own; so that the extremity of the tourmaline acted on by positive electricity, repels the needle to which it is presented, and the other extremity, possessing negative electricity, attracts the needle.

Fig. 3, is a spirit of wine blow-pipe, nearly on the plan of that invented by Mr Paul. It is made of brass, and consists of the following parts.

\(a\) Is a hollow oval frame about five inches in its longest dimension, which supports the pillar \(d\) and the two lamps \(b\) \(c\), which may burn either oil or alcohol, but the latter is the best. The rim \(e\) slips upon the pillar \(d\) as low as the shoulder of the latter will permit, but the rim may be raised at pleasure and kept fast by the screw peg \(f\). The rim supports the boiler \(g\) which is a single hollow piece of thick brass containing about an ounce of alcohol, and has four openings, viz. three at top \(h\) \(i\) \(k\), and one at bottom to receive the tube \(o\). This latter is long enough to reach the level of the outside of the top of the boiler, and consequently the alcohol within the boiler cannot readily boil over into the tube, and the opening \(k\) which corresponds with it, is closely shut by a screw stopper, hollowed out a little beneath, to allow the free passage of the vapour down the tube. Here the vaporized alcohol is prevented from condensing at the point \(o\) by the contiguity of the flame of the lamp \(b\), and as it passes on through the hollow \(p\) \(q\) into the jet tube \(r\), it is immediately kindled by the flame of the lamp \(c\), and the united flames are compelled sidewise with such violence as to form a long pencil of blue flame, attended with a considerable roaring noise. This continues as long as any alcohol is left in the boiler, which allows ample time for most blow-pipe operations. The boiler is filled at the opening \(h\). The centre hole \(i\) is nicely fitted with a small brass plug kept down by a thin slip of iron \(l\), the other end of which slips over the top of the upright pillar \(d\), and is confined between two flat screw-plates \(m\) \(n\). The use of this is as a safety valve to take away all danger of the boiler bursting by the confined vapour not being able to escape fast enough through the jet-pipe \(r\), for when the internal pressure is great, the elasticity of the iron spring \(l\) allows the valve \(i\) to rise sufficiently to let out part of the enclosed vapour. The screw stoppers \(h\) and \(k\) are made still tighter by collars of leather, as is the part where the tube \(o\) joins the boiler. The jet-pipe \(r\) has a complete rotary motion, so that the flame may be impelled in any direction. This is effected by turning in the form of a ball that part of the pipe which is inclosed in the hollow \(p\) \(q\).

But this blow-pipe, although an elegant philosophical apparatus, will not be found answer where a great degree of heat is required to be kept up for a considerable time. Other contrivances, therefore, of a simpler nature, have been proposed; and perhaps the best of these is the blow-pipe which is used by the mouth. The following is a description of a blow-pipe of this kind.

Fig. 4 represents this blow-pipe. \(a\) Is a brass tube, having a circular enlargement \(c\), for the purpose of condensing the moisture which is blown from the lungs; the smaller end \(d\) is moveable round the centre \(c\), so that any degree of obliquity may be given to the flame. Fig. 5, is a separate jet-pipe with a small opening, which is screwed on the blow-pipe at \(d\); and it may be convenient to have two or three jet-pipes of different sizes, according as a larger and more moderate, or a smaller and more intense flame is wanted. \(b\) Is a piece of ivory which slips on the larger end, for the purpose of being applied to the mouth, as being more agreeable.

The best kind of flame for blowing through with the common blow-pipe is a wax or tallow candle with a very large wick, which should be kept snuffed moderately low, and the wick turned a little aside from the pipe. A spirit lamp is sometimes used, which makes a perfectly clear flame without smoke, but weak when used in this way. There is a kind of knack in blowing with the mouth, which is not easily described, and requires a little practice to be performed with ease. As the flame must often be kept for several minutes, the act of respiration must be carried on through the nostrils without interruption, and the stress of blowing must be performed merely by compression of the cheeks upon the air in the mouth.

The substance to be heated is placed either on a piece of charcoal or a metallic support. When the former is used, a large close well-burnt piece of charcoal must be chosen, a small shallow hole scooped out with a knife, and the substance laid upon it. The charcoal itself kindles all round the hole, and the hole is thus gradually enlarged; and the heat too is kept up round the substance much more uniformly than when a metal support is used. At the same time however the chemical effect produced by heated charcoal should not be forgotten, particularly the reduction of metallic oxides, and the deoxygenation of the fixed acids; so that, for example, a small heap of minium or litharge heated red-hot on charcoal... charcoal by the blow-pipe, is speedily reduced to a globule of metallic lead; the phosphates are partially reduced to phosphurets, &c.

For a metallic support, platina is in general by far the best material. A small spoon of this metal, the shank of which may be fixed in a cork when held, and a small silver cup, the shank of which is fixed into a wooden handle, may be used in fusions with borax or alkaline fluxes. A small forceps lately brought into use, and made entirely of two thin pieces of platina joined by rivets, and bent, will be useful in holding any small hard substance in the blow-pipe flame for any length of time, without danger of the points of the forceps melting; and it is also found that this metal is so much worse a conductor of heat than any other, that the forceps never gets too hot for the naked fingers to touch at the bend.*

Fig. 6. represents a portable pocket blow-pipe, invented by Dr. Wollaston, and of its actual size. The interior tube is longer than the exterior, that it may be readily withdrawn; and the upper edge of the large end is turned outward, to diminish the effort of the lips requisite for retaining it in the mouth.

Fig. 7. represents the whole apparatus, one half of its real dimensions, and connected for use. The small extremity a is placed obliquely at an angle of about 120°, that the flame impelled by it may be carried to a more convenient distance from the eye, and thus answering the purpose of a longer blow-pipe. This oblique piece a is composed of three parts, the largest of which is made stronger, that it may not be injured by use. One end is closed, and into the other is inserted a small peg of wood, perforated so as to receive the tip which is intended to be occasionally separated, for the purpose of passing a fine needle into it, to remove obstructions†.

PLATES CCCLII. and CCCLIII.

Fig. 1. Diamond,—spheroidal, with 48 convex faces. Fig. 2. Zircon,—the primitive form an octahedron with isosceles triangles. Fig. 3. Zircon,—rectangular four-sided prism terminated by a four-sided pyramid set on the lateral faces. Fig. 4. Hyacinth,—a dodecahedron formed from a rectangular four-sided prism terminated by a four-sided pyramid set on the lateral edges. Fig. 5. Chrysoberyl,—double four-sided pyramid flattened, having the summits truncated. Fig. 6. Chrysolite,—a compressed eight-sided prism, terminated by an eight-sided pyramid, whose sides correspond to those of the prism, and whose summit is truncated by a convex surface. Fig. 7. Augite,—the primitive form, an oblique four-sided prism with rhomboidal bases. Fig. 8. Common form of augite,—a short, eight-sided, compressed prism, terminated by two oblique faces. Fig. 9. Pyroxene,—a six-sided prism with two broad and four narrow faces, and bevelled at the extremities. Fig. 10. and 11. other forms in which the prisms are terminated by several oblique faces with a truncated summit. Fig. 12. Vesuvian,—a four-sided prism with the edges truncated, and terminated by four oblique and one horizontal face.

Fig. 13. Garnet,—primitive form, a rhomboidal dodecahedron. Fig. 14. Trapezoidal garnet,—composed of 24 faces, which are equal and similar trapezoids. Fig. 15. Grenatite,—a six-sided prism with the greater angles at each base truncated. Fig. 16. Two crystals of the same crossing each other obliquely. Staurolite, oblique angle, of Hauy. Fig. 17. Corundum,—two six-sided pyramids united by the bases, with the summits and angles truncated. Fig. 18. A six-sided prism, having the alternate angles at each base truncated. Fig. 19. Topaz,—an eight-sided prism terminated by an obtuse four-sided pyramid at one extremity, and by a different one at the other. Fig. 20. A similar prism with six of the terminal edges truncated. Fig. 21. Tourmaline,—primitive form, which is an obtuse rhomboid. Fig. 22. A nine-sided prism, terminated at one extremity by a six-sided summit, and by a three-sided summit at the other. Fig. 23. Axinite or Thummerstone,—primitive form, which is a rectangular four-sided prism, whose bases are oblique-angled parallelograms. Fig. 24. A secondary form, same prism, having the alternate lateral and terminal edges truncated. Fig. 25. Rock-crystal,—A double six-sided pyramid. Fig. 26. A six-sided prism, terminated at each extremity by a six-sided pyramid, having the alternate angles at the opposite bases slightly truncated. Fig. 27. Feldspar,—the primitive form, which is an oblique-angled parallelopiped. Fig. 28. An oblique four-sided prism. Fig. 29. A six-sided prism with four of the angles truncated, and the two extremities bevelled. Fig. 30. The same prism, with four of the terminal edges truncated. Fig. 31. An oblique four-sided prism, bevelled and truncated at the extremities. Fig. 32. Chalcolite,—the outer rhomboid marked with black lines parallel to the sides of the black internal rhomboid. Fig. 33. Foliated Zeolite, or Stillbite,—compressed four-sided prism, terminated by a four-sided summit set on the lateral edges. Fig. 34. A six-sided prism with two solid angles at each extremity, truncated. Fig. 35. Cubic Zeolite, or Analcime,—the cube with all the solid angles truncated. Fig. 36. Cubic Zeolite, or Chabasite,—composed of three rhomboids. Fig. 37. Crocidolite,—a double crystal composed of two dodecahedrons crossing each other at right angles. Fig. 38. Hornblende,—primitive form, an oblique four-sided prism, whose base is a rhomboid. Fig. 39. Basaltic Hornblende,—a six-sided prism terminated at one extremity by four trapezoidal planes; and at the other by a bevelment, the planes of which are pentagons. Fig. 40. Tremolite,—an oblique four-sided prism, having the acute angles truncated and terminated by a dihedral summit; Fig. 43. Calcareous Spar, or Carbonate of Lime,—primitive form a rhomboid.

Fig. 44. A very obtuse rhomboid.

Fig. 45. An acute rhomboid.

Fig. 46. Approaching to the cube.

Fig. 47. Double six-sided prism, known by the name of Dog-tooth spar.

Fig. 48. A six-sided prism, terminated at each extremity by a trihedral summit whose faces are pentagons.

Fig. 49. Also a six-sided prism with trihedral summits; but the bases of the terminal pentagons are enlarged in consequence of the inclination of the lateral faces.

Figs. 50, 51, 52. Other forms of calcareous spar.

Fig. 53. Sulphate of Lime,—primitive form.

Figs. 54, 55. Common forms.

Fig. 56. Sulphate of Barytes,—primitive form.

Figs. 57, 58, 59. Common forms of sulphate of barytes.

Fig. 60. Sulphate of Strontites,—primitive form.

Fig. 61. Common form.

Fig. 62. Borate of Soda,—primitive form.

Fig. 63. One of the common forms.

Fig. 64. Carbonate of Soda,—primitive form, an acute octahedron.

Fig. 65. One of the common forms, having two angles at the base truncated.

Fig. 66. Nitrate of Potash,—primitive form, a rectangular octahedron.

Figs. 67, 68. Common forms.

Fig. 69. Sulphate of Magnesia,—the common form.

Fig. 70. Borate of Magnesia,

Fig. 71. Sulphur,—primitive form.

Fig. 72. Common form.

Fig. 73. Mercury, Native Amalgam,

Fig. 74. Cinnabar.

Figs. 75, 76, 77. Red Silver Ore.

Figs. 78, 79, 80, 81, 82. Crystals of Copper Ore.

Figs. 83, 84, 85, 86, 87, 88, 89, 90, 91, 92, 93. Crystals of the Ores of Iron.

Fig. 94. Carbonate of Lead.

Fig. 95. Sulphate of Lead.

Figs. 96, 97. Molybdate of Lead.

Figs. 98, 99, 100. Crystals of Tin.

Fig. 101. Oxide of Zinc.

Fig. 102. Sulphuret of Zinc.

Fig. 103. Sulphuret of Antimony.

Figs. 104, 105. Crystals of Cobalt.

Fig. 106. Manganese.

Fig. 107. Sulphuret of Arsenic.

Fig. 108. Tellurium,—primitive form.

Fig. 109. Common form.

Figs. 110, 111, 112, 113. Crystals of Titanium.

INDEX.

A.

ACANTICONE. See Pflaumite, p. 161

Actinolite,

Adamantine spar,

Adhesive flake,

Adularia,

Agaric mineral,

Agate, varieties of,

Alum stone,

Alumina, native,

Aluminous schistus,

Amber,

Amethyst,

Amianthite,

Analcime. See Cubizite,

Andalusite,

Anhydrite,

Antimony, ores of,

Apatite,

Arragonite,

Arctizite,

Arendalite. See Pflaumite,

Argillaceous genus,

Arsenic, ores of,

Asbestos,

Asparagus stone,

Augite,

Axinite,

Azurite,

B.

Baryte, carbonate of,

Baryte, sulphate of,

Barytic genus,

Basalt,

Beryl,

Bismuth, ores of,

Bitumenous marl flake,

Black lead. See Graphite,

Black schorl,

Blende,

Bole,

Bolognian spar,

Boracite,

Borax,

Brown spar,

Calamine,

Calcaceous genus,

spar,

sinter,

tufa,

Caledony,

Capillary salt,

Carnelian,

Cat's eye,

Celestine,

Cerite,

Cerium, ores of,

Chabasite. See Cubizite,

Chalk,

Chlorite,

Chromate of iron,

Chromium, ores of,

ib.

Chrysoberyl,

Chrysolite,

Chrysoprase,

Cinnabar. See Mercury,

Clay, common,

pipe,

potters,

variegated,

slaty,

indurated,

flute,

Clink-stone. See Phonolite,

Coal,

Cobalt, ores of,

Columbium, ores of,

Combustibles, clats of,

Copper, ores of,

Corundum,

Croftstone,

Cryolite,

Cube spar,

Cubizite,

Cyanite,

D.

Diamond,

Diamonds, celebrated,

Dolomite, | Index | MINERALOGY | |-------|------------| | Diamite, Drawing slate, E. | Lava, p. 202 | | Emerald, Every, Epsom salt, Epsafe, F. | Lazulite, p. 185 | | Feldspar, common, compact, Figure stone, Flit, Flints, formation of, theories of, flint gun, manufacture of, Flaky slate, Flint stone, Flor, Spar, Forn earth, Fellers earth, G. | Lead, ores of, p. 159 | | Gelolinite, appendix, Garnet, precious, common, Bohemian, black, Glauber salt, native, Gal, ores of, mines of, Graphite, Green earth, Garnatite Ge flints, manufacture of, Gypsum, H. | Lepidolite, p. 157 | | Hematites. See Iron ores, Heavy spar, Hiatoire, Hollow spar, Henstone, Henstone, Iplintery, conchooidal, Hacinth, Hailite, Harargillite, I. | Limestone, p. 210 | | Javer, Egyptian, striped, porcelain, common, agate, opal, Iodophorhalite, Iridium, ore of. See Platina, Iron, ores of, L. | Lithamarga, p. 158 | | Labrador stone, Lemonite, | Loam, p. 178 | | Lydian stone, M. | Magnesia, native, p. 179 | | Magnetite genus, Magnetic iron ores, Malachite ore of copper, Manganese, ores of, Marble, varieties of, Marl, Meionite, Melanite, Melilite, Menachanite, Merlinit, Mercury, ores of, Metotype. See Fibrous Zeolite, Mica, Mineral oil. See Petroleum, pitch, Mineralogy, history of, Minerals, classification of, external characters of, table of, Mountain butter, Cork, Soap, Muriate of copper, Native vitriol, alum, Glauber salt, nitre, Natrolite, Nephrite, Nickel, ores of, Nigrine, Obidian, Olivine, Oolite, Opal, mines of, common, wood, Orpiment, Osmium. See Platina, Palladium. See Platina, Pearl-stone, Peafowl, Petroleum, Phonolite, Phosphorite, Pinite, Pisolite, Piilazide, Pitch-stone, Plasina, ore of, Platina, ore of, Plumbago. See Graphite, Polishing flate, Porcelain-earth, Pot-stone, Prase, Prehnite, Pyrites, copper, iron, Pyrope, Pyrophylsite, Quartz, common, rosy red, ferruginous, Rhodium. See Platina, Rhomb spar, Rock crystal, Salt, Sahlite, Sal ammoniac, Salts, clas of, Sapphire, Scapolite, Schiller-stone, Schorl, Schorlite, Schorlous beryl, Sea-froth, Selenite, Semi-opal, Serpentine, Siliceous genus, Siliceous schistus, Silver ores, Sinter, calcareous, Slaty spar, Smaragdite, Soda, Somnite, Specular iron ore, Spinelle, Spodumene, Steatites, Strontian genus, Strontian, carbonate of, Sulphate of, Stilbite. See Foliated Zeolites, Sulphur, Swine-stone, Talc, Tantalium, ores of, Tellurium, ores of, Thumer-stone. See Axinite, Tin, ores of, Titanium, ores of, Topaz, Tourmaline, Tremolite, |