mineral

Muscovite mica

Muscovite, KAl₂(AlSi₃O₁₀)(OH)₂

AI-generated identification · may be incorrect

Usually colorless, silvery, pale green, or amber; vitreous to pearly luster; excellent basal cleavage into flexible transparent sheets. Mohs hardness 2–2.5; monoclinic crystal structure; specific gravity about 2.8–2.9.

Identified August 10, 2026More mineral →

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Physical properties

Formation & geological history

Forms chiefly in felsic igneous rocks such as granite and pegmatite, and in metamorphic schist and gneiss through potassium-rich hydrothermal or metamorphic processes. Individual crystals may be millions to billions of years old, depending on the host rock.

Uses & applications

Used historically as electrical and thermal insulation, and today in paints, plastics, drilling fluids, cosmetics, and construction compounds; attractive sheets are collected as mineral specimens.

Geological facts

Its name derives from the Russian use of mica sheets in windows. The specimen’s broad, translucent, easily separated sheets and silvery sheen are characteristic.

Field identification & locations

Identify it by peeling into elastic, clear-to-translucent sheets that do not dissolve in water; it commonly occurs in granitic pegmatites, schists, and gneisses worldwide, especially India, Brazil, Russia, and the United States.