71. Common Garnet.—A very inferior variety of garnet, of brown or greenish brown colour, is found in our own country, and particularly amongst rocks near Huntley, in Aberdeenshire, Scotland. These garnets, however, are, in general, so soft as to be of little value to the lapidary; and consequently are seldom cut or polished for ornamental purposes. But being easily fused, and abounding in iron, they are occasionally employed as a flux in the smelting of rich iron ores: and as an addition to poor ones.
72. Syrian Garnets are distinguished by their violet or purplish tinge. Some writers state that they have their name from the word Soranus, which signifies a red stone; and others from Sirian, a town in Pegu, where they are said to be found in great beauty.
73. Pyrop Garnets are of a dark blood-red colour, which, when the stones are held between the eye and the light, falls strongly into yellow: they are chiefly brought from Bohemia: are employed in almost every kind of jewellery, and generally set with a gold foil. At Waldkirch, in Suabia, there are twenty-four mills for the cutting and polishing of pyrop garnets: and 140 masters are occupied in manufacturing these stones.
74. Vesuvian is a liver-brown kind of garnet, that was originally found among rocks ejected from Mount Vesuvius; and in the vicinity of which mountain it still occurs in considerable abundance. At Naples it is cut into stones for rings and other ornaments. Vesuvian has of late years been found in other parts of Europe; and even at Kilranelagh, and Donegal, in Ireland.
75. Cinnamon Stone is a kind of garnet of hyacinth-red colour, which is found in angular and roundish pieces among the sand of rivers in the island of Ceylon. It is cut as a precious stone; and, when of good colour, and free from flaws, is of considerable value.
QUARTZ FAMILY.
76. COMMON QUARTZ is a hard and foliated substance, usually of white or grey colour, and more or less transparent.
It is generally found in shapeless masses, which are nearly thrice as heavy as water, and the fracture of which is glassy. When crystallized, it most commonly has the form of a six-sided prism, terminated by a pyramid of six sides.
This kind of stone forms a constituent part of many mountains, and is very common in our own, as well as in most other countries. It is sufficiently hard to scratch iron and steel; and it has the property, after having been several times successively made red-hot, and dipped into water, of communicating to that fluid a certain degree of acidity.
Quartz is employed, in place of sand, for making the finer kinds of glass; and also in the manufacture of porcelain. For the latter purpose great quantities are collected from the mountains of Wales, ground into powder, and in that state shipped to Liverpool, and other parts. After having been burnt and reduced to powder, it is sometimes mixed with clay, and formed into bricks for the construction of glass furnaces: these are capable of resisting the intense heat which is requisite in the fusion of glass.