Chrysoberyl (Gr. gold, and beryl), a gem, also called cymophane ( wave, and to appear), so named from a peculiar opalescence it sometimes exhibits. It occurs in crystals derived from the rectangular prism. It is of vitreous lustre, specific gravity 3.5 to 3.8, and hardness 8.5. The crystals arc transparent or translucent, and of light shades of green, colored by oxide of iron and sometimes probably by chrome. The finest transparent crystals are cut with facets, and are then known and highly prized by the name of oriental chrysolite or oriental topaz. If opalescent, they are usually cut en cabochon, and unless very brilliant are of little value. The mineral consists of nearly 80 per cent, of alumina and 20 of glucina; a small proportion of oxide of iron is usually present. It is found in Brazil and Ceylon, in rolled pebbles among alluvial deposits; in the Ural, associated with beryl in mica slate; in Haddam, Conn., in granite, with garnet, beryl, etc. It also occurs in Vermont, and near Saratoga, N. Y.