MICA

(Lat. mico, / shine.) A mineral generally found in thin elastic laminae, soft, smooth, and of various colours and degrees of transparency. Silica, alumina, potash, and oxide of iron are its principal components. It is one of the constituents of granite. In some parts of Siberia and elsewhere it forms an article of trade, often known under the name of Muscovy gla . [s. 751]