Chrysoberyl

Chrysoberyl (Gr., 'golden beryl'), a gem almost as hard as sapphire, and the finer specimens of which are very beautiful, particularly those which exhibit an opalescent play of light. Lapidaries sometimes call it oriental or opalescent chrysolite. It is of a green colour, inclining to yellow, semi-transparent, or almost transparent, and has double refraction. It occurs crystallised in six-sided prisms; often in inacles, or twin crystals. It is found occasionally in granite, but more frequently in gneiss and mica-schist; sometimes it occurs in sandstone or in alluvial soil derived from the disintegration of schistose rocks. Localities for its occurrence are the Ural Mountains, Ceylon, Pegu, Brazil, and Connecticut. It is composed of alumina, glucina, and small proportions of ferric oxide, titanic acid, and sesquioxide of chromium—the alumina being about 80 per cent. of the whole. The chrysoberyl of the ancients was a different mineral, probably the Chrysoprase (q.v.) of the moderns.