GRANATE, or GARNET: a genus of fossils ranked among the siliceous earths; but, according to M. Magellan, analogous to gems, all of them being composed of the siliceous, argillaceous and calcareous earths, with a greater or less proportion of iron. The opaque and black garnets contain about a fifth part of iron; but the diaphanous ones only th, according to Bergman. The garnets, properly so called, contain a greater quantity of siliceous earth than the shirls, and both are now justly ranked with the siliceous earths. The general properties of the garnet, according to Cronstedt, are as follow: 1. It is more fusible as it contains less metallic matter, and is more transparent or glassy in its texture. 2. Mixed with salt of kelp, it may, on a piece of charcoal, be converted into glass by the blow-pipe, which cannot be done with flint. 3. The most transparent garnet may, without any addition, be brought to a black opaque slag by the flame means. 4. It is never, as far as is hitherto known, found pure, or without some mixture of metal, especially iron, which may be extracted by the common methods. 5. The garnet matter, during the crystallization, has either been formed in small detached quantities, or else has had the power of shooting into crystals, though closely confined in different substances: since garnets are generally found dispersed in other solid stones, and oftentimes in the harder ones, such as quartz and chert. Fabroni informs us, that the garnet is easily melted by means of borax or the vegetable alkali. Its specific gravity is greater than that of the precious stones; viz. from 3600, and even from 4400
to 5000. According to Brunich, most of the garnets strike fire with steel. Granary.
Cronstedt observes, that the metallic calces, when mixed with other earthy substances, make great alterations in their fusibility; iron, for instance, in the argillaceous and micaceous earths, renders them fusible, tho' otherwise they are not so. Hence there may be some reasons for considering the garnet as a quartz impregnated with iron; yet on the whole he thinks it will be better to call the garnet a stone of a different order, until we have experiments sufficient to warrant us to reduce the number of earths. The garnet earth is never found but in an indurated state; and is divided into the garnet properly so called, and shirl or cockle; though this perhaps is owing more to the figure of their crystals than any thing else. The species are,
1. The granatus, or coarse-grained garnet; a heavy hard stone, crystallizing in form of polygonal balls, mostly of a red or reddish brown colour. It is found of a reddish brown and whitish or pale yellow, in different parts of Sweden.
2. The granatus crystallizatus, or crystallized garnet, is reckoned among the precious stones, but varying in its colour and form of its crystal more than any of them. Sometimes it is of a deep and dark red colour; sometimes yellowish or purplish; sometimes brown, black, or opaque. It is inferior both in lustre and hardness to the other gems, yielding to the file, although it will strike fire with steel. The crystals are sometimes irregular, but frequently assume rhomboidal, tetradecahedral, and almost all other regular forms.
Wallerius makes the specific gravity of the garnet from 3600 to 3900, and even 4400; Brissen makes it 4100; and Cotes says that the garnets of Bohemia are 4360, those of Sweden being 3978. The most esteemed is the Syrian garnet; which is of a fine red, inclining to purple, very transparent, but less beautiful than the oriental amethyst. This, according to Magellan, is the amethystizontas of Pliny; and is found in Syria, Calcutta, Cananor, Camboya, and Ethiopia. The foranus of the ancients was another kind of garnet of a red colour inclining to yellow, called vermeille by the French, and giacinto guarnacino by the Italians; the former having the name of rubino di rocca among the last mentioned people. The name Soranus comes from Sorian or Surian, a town of Pegu, from whence these gems are brought.
Sometimes the garnets have a yellow colour, in which case they obtain the name of hyacinthi. Like other gems, they are divided into oriental and occidental; but this means in fact no more than more or less valuable; the finest stones being always called oriental, wherever they come from. Some very fine ones are found in Bohemia; they are also met with in Hungary, at Pyrna in Silesia, S. Sapho in the canton of Berne in Switzerland, in Spain, and in Norway. Their colour is supposed to proceed from iron; and, according to M. Saussure, even the finest oriental garnets attract the magnetic needle at a small distance. In the focus of a good burning-glass the garnet melts into a brown mass, which is attracted by the magnet; which shows that iron enters into its composition in a considerable proportion. Some garnets, however, contain a little gold; and some, called by the Germans zingrauen, contain tin. M. Magellan is of opinion, that
Granate, the lapis alabandicus of Pliny, and another gem which
II Grandee. he mentions of a deep purple, were both true gar-
nets.
3. The cockle or shirl. See COCKLE.
The garnets abound so much with iron that they are
sometimes worked with profit as ores of that metal; in
which case no notice is taken of the natural character
of the stone, in the same manner as is done with clays
and jaspers that contain iron; for in these the quanti-
ty of metal is gradually augmented, until at last they
acquire the appearance of iron itself. The greatest
part of this genus, however, contain only from six to
twelve per cent. of iron, which is too poor to be work-
ed any where with advantage as an ore of that metal.
When any of the garnet kind are to be tried for the
metal they contain, the iron ought to be melted out
of them by the common process; and if the garnet at
the same time contains tin or lead, these will likewise
be included in the iron. They may be extracted out
of it, however, by a heat gradually augmented; the
lead and tin sweating out in form of drops, though al-
ways somewhat mixed with iron. None of the garnet
kind have yet been found in the form of an earth prop-
erly so called; though at Swappawari in Lapland,
there is found a hole which has the same figure with
the garnet; and the hornblende of the Swedes, which
is somewhat harder than this bole, has often the ap-
pearance of a cockle.