N. Carolina, U.S.A. It is quarried and cut to a large extent as a gemstone.
6.—Demantoid or Bobrovka Garnet.—This is a calcium ferric garnet from the Syssersk district on the Western slopes of the Urals. It is softer than any other garnet, but its colour—that of a rather yellowish green emerald—has made it a valuable and popular stone. Unfortunately dealers and jewellers have given it names to which it has no right. It was called "Uralian emerald" at one time, and now it is generally called olivine, the proper designation of an entirely different stone, namely, the peridot. Demantoid is in reality only one of a number of sub-varieties, having a wide range of colours and of constituents, of calcium ferric garnet, but it is the only one that is appreciated as a precious stone. The most esteemed colour is near that of the emerald, but the yellowish, green, the pistachio, asparagus and olive-green stones, as well as the liver-coloured stones, are not without beauty, owing, doubtless, to the lustre of the polished facets of the gem, and to its high refractive and dispersive powers, which impart to it a brilliancy and fire possessed by no other green stone. Demantoid appears to advantage under artificial illumination. Its hardness is about 6°—rather too low for a ring-stone. The specific gravity of three specimens proved to be as follows:
Green-yellow, 3·854; Pistachio-green, 3·848; Emerald green, 3·849. Although demantoid has been frequently analysed its constitution has not been brought precisely into line with the garnet formula. It is thought that the emerald green specimens owe their distinctive hue in part to the presence of chromium.
7.—Uvarovite, or Calcium Chromium Garnet.—This variety always contains some alumina in place of part of the chromium sesquioxide. It is of a fine emerald green, has the hardness 7°5 and the density 5·5, but it rarely admits of being cut as a gem owing to its occurrence in very small crystals, or its want of complete transparency. Of other garnets mention may be made of