Definition of "muscovite" [muscovite]

• A potassium aluminum silicate mineral, KAl2(AlSi3O10)(OH)2, the most common form of mica, which ranges from colorless or pale yellow to gray and brown, has a pearly luster, and is used as an insulator. Also called white mica. (noun)

American Heritage(R) Dictionary of the English Language, Fifth Edition. Copyright (c) 2011 by Houghton Mifflin Harcourt Publishing Company. Published by Houghton Mifflin Harcourt Publishing Company. All rights reserved.

• "Very large sheets or crystals of muscovite form in a pegmatite."
• "The two micas used as a commodity are: brown mica or phlogopite which contains iron and magnesium; and the "reddish, green, or white (or clear) mica" or muscovite which contains potassium and aluminum."
• "These layers can be seen in muscovite mica specimens because it can be split (mineralogists call this feature cleavage) into very thin, flexible, transparent layers."