[L. mica, a small bit.] A mineral found in granite and most of the other primary rocks. It easily divides into glittering plates of great thinness. It is so transparent that it is used in Siberia, China, Peru, and other countries as a substitute for glass in windows. Mica is sometimes preferred to glass for lanterns, and is also used for doors of stoves, as it is not so liable to break with sudden changes of temperature.