GARNET, in mineralogy, is a species efthe flint genus, of which there are two sub-species, vir. the precious, and com mon garnet. The precious, or Oriental, garnet is red, but of various shades ; it occurs seldom massive, more often dis seminated, and in original roundish grains -and small pieces. It occurs most com monly crystallized, either as a dodecae dron, or as a double eight-sided pyramid. Its specific gravity is about 4.3, and it consists of Silica 35 75 Alumina . . . . 27,25 Oxide of Iron . . 36.0 Manganese . . . 0.25 99.25 Loss 0 75 100 .---'=— Before the blow-pipe it melts into a black enamel. .
The common garnet is brown or is not so heavy as the precious, and h composed of Silica1 26 46 Alumina . . . . 22.70 Lime 17 91 Iron 16.25 - — 83.32 Ross . , . 16.68 100 ..--...
It is more easily melted than the preciou garnet.
" The garnet varies more than an: I other gem, both in the form of its crys ' tals, and in its colour ; some being of deep red, some yellowish, or of a purpl tint, and others brown, blackish, an quite opaque. They are generally of spherical form, and never crystallize wit less than twelve sides. The prevailin colour is a fine red, and the mean siz that of a large pea, though they ar found from the size of a grain of sand t three or four inches in diameter. Thos imbedded in granite are in general of th smallest size, but at the same time di most transparent. Among the garnets which are called Oriental may be distin guished three different shades, known in commerce by as many different names. The garnet of a fine red colour, and free from, any mixture, is called a carbuncle. Garnets are found in almost every country where primitive rocks exist. Switzerland and Bohemia are the two countries in Eu rope which furnish them in the greatest abundance. Those of Bohemia have a tint of orange mixed with the red, from whence some have given them the name of rubies. These stones are likewise
found in Hungary, at Pyrna in Silesia, in Spain, and In Norway. At Bareith, a town in Germany, garnets are found in little irregular masses of a fine red co lour, and abundantly disseminated in a green semi-transparent stone called ser pentine. As they are susceptible ova fine polish, the inhabitants form them into se veral pretty trinkets and other articles of jewelry. Black garnets are met with in different situations. Ramond, professor of natural history at Tarbes, collected some from a mountain of the Pyrenees in the neighbourhood of Barege ; Rome de l'Isle found them in the diamond mines of Bra zil; and Brongniart tells us that they have been discovered in a volcanic rock near Vesuvius, and in the basaltes of Bohemia. When garnets are perfectly transparent, and hard enough to bear a fine polish, the lapidaries cut them into facits, to be em ployed as jewels. In Bohemia there are places where they work the garnets which are found in the neighbourhood. There are workshops also at Friburg, in Brisgaw, for the garnets which are col lected from several of the Swiss moon'. tains. The impure garnets are used to advantage as a flux, when they are found near iron-mines, as they not only facilitate the fusion of that metal, but add some thing to the mass, by contributing the por tion of iron which generally enters into their composition. The quantity indeed is sometimes so great, that they have been said to yield 40/b. in the cwt. and consequently worth smelting alone for the sake of their produce." See Wood's " Zoography," to which we Have been indebted in the articles (CAE. and Fr cus.