Definition of: mica

(mī′kə) noun
Any of a class of silicates, crystallizing in the monoclinic system and having eminently perfect basal cleavage, affording thin, tough laminae or scales, colorless to jet-black, transparent to translucent, and of widely varying chemical composition. The better grades are extensively used for electrical insulation; the transparent varieties are loosely called isinglass. [<L, crumb; infl. by micare glitter]