Mi'că, n.

n. [Lat. mica, crumb, grain, particle; Fr., It., & Sp. mica.] (Min.) A mineral capable of being cleaved into elastic plates of extreme thinness. It is either colorless or presents some shade of light-brown, gray, smoky-brown, black, and occasionally green or violet. It is generally more or less transparent, and is used, like glass, in lanterns, and in the doors of stoves. There are three or four species of mica, differing in composition and crystalline form. It was once called glimmer. Mica is an essential constituent of granite, gneiss, and mica slate. Dana.