mineral

Muscovite mica

Muscovite, KAl₂(AlSi₃O₁₀)(OH)₂

AI-generated identification · may be incorrect

Typically colorless, silvery, pale brown, or golden; pearly to vitreous luster, transparent-to-translucent sheets, and perfect basal cleavage. Mohs hardness 2–2.5; monoclinic and commonly forms flexible elastic flakes, with specific gravity about 2.8–2.9.

Identified August 10, 2026More mineral →

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Physical properties

Formation & geological history

Forms mainly in granite, pegmatite, and mica schist through crystallization from silica-rich magma or metamorphism. Most specimens are Precambrian to Phanerozoic, though mica forms in many geologically young settings.

Uses & applications

Used industrially as electrical and thermal insulation, joint compound, paints, plastics, and cosmetics; attractive specimens are collected but generally have limited jewelry use.

Geological facts

Its sheet-like cleavage allows it to split into exceptionally thin, transparent layers that were historically used as window material. Golden varieties may be sold as “golden mica,” though color does not necessarily indicate a separate species.

Field identification & locations

Identify it by flexible, elastic sheets, perfect one-direction cleavage, and light-colored pearly surfaces; distinguish it from brittle, darker biotite. Common localities include India, Brazil, Madagascar, Russia, and U.S. pegmatites.