a precious stone of the second order, of which the varieties are, Siberian, ruby-coloured, reddish, green, brown, blue, and black; mother of emerald, dark green; lapis crucifer, or the cross stone; bar schorl; horn blend, black, green, or blue; Cianie, blue schorl; Thumstein; Laxman's quadrangular schorl.
Transparent schorl is crystallized in polygonal prisms, generally with four, five, or nine sides; some of them are so fine as to pass for gems of the first order, especially for the emerald. In the semitransparent schorls there are likewise some of great beauty, as the ruby-coloured, lately discovered in Siberia by counsellor Herman, in a bed of reddish argilla, mixed with fragments of felt spath, quartz, and mica, on a low granite mountain. The bed of argilla is evidently produced by the decomposition of granite; which operation Herman supposes must have set at liberty the ruby schorl formerly pent up in the chinks or fissures of the decomposed part of the mountain. The discovery is quite new, no such species being before known, as it is as hard as the first order of precious stones, the diamond excepted, takes a fine polish, and equals in colour the oriental ruby, though not in transparency.
Its structure is made up of fine cylindric columns, like needles collected into bundles or tresses, lying one on another in different directions, whilst each individual column is made up of fine plates or laminae, like the gems. It is fusible per se into a white transparent glass, and melts imperfectly with borax when calcined, as it does with microcosmic salt and mineral alkali, into a small vitreous globe, with little spots of a white enamel colour. Acids have no effect upon it, even when calcined. Lastly, it loses its colour in the fire, after having first turned blue. The mother of emeralds is likewise a semitransparent schorl, in the opinion of some able naturalists, although Mr Born affirms it to be a jade, we know not upon what authority.
The structure of the semitransparent schorls, and some of the transparent that are not so perfectly diaphanous as to conceal their texture, is obscurely sparry; but that of the opaque is either filamentous, like asbestos, or hard and brittle like threads of glass, or it is composed of fæces. Of this last kind is that called horn blend, which is generally green or black; but there is a beautiful variety of it found on the mount St Gotthard, in Switzerland, of a fine sky-blue colour covered with silver talk. Bar schorl has been found on the Carpathian mountains crystallized in prisms. Lapis crucifer, or the cross stone, is found sometimes near Brazil in Switzerland, and there named Tauffstein, or chertening stone; but oftener at Thum in Saxony, and therefore named there Thumstein. It is a schorl in form of a cross: that of Brazil consists of two hexagonal crystals. The exact crystallization of the other is unknown to us.
Most countries produce schorls. Russia is particularly rich in schorls. It is even difficult to point out all the different places of the empire which produce them; but we shall take notice of those most remarkable, particularly new discoveries. The ruby-coloured schorl mentioned above was found by Mr Herman at Sarapouisky, a village in the government of Perm, ten versts from Mourinisky Slabode, in Siberia. The Siberian inspector, Mr Laxman, has lately discovered in the mountain Alpefria, on the river Sleudanka near the lake Baikal, the following new schorls. First, a green transparent schorl, of so brittle a nature as not to bear carriage without breaking into small pieces truncated. Pallas is positive in declaring this dark green schorl a hyacinth. This last has often some of the small yellowish white garnets sticking in it, described in the arti-