mineral

Muscovite

Muscovite, KAl2(AlSi3O10)(OH)2

AI-generated identification · may be incorrect

Hardness: 2-2.5 on Mohs scale; Color: Colorless, silvery, white, grey, yellowish, brownish, or greenish; Luster: Vitreous, pearly, or silky; Crystal structure: Monoclinic, forms tabular crystals or sheet-like masses; Cleavage: Perfect basal cleavage yielding extremely thin, flexible elastic sheets;…

Hardness: 2-2
Luster: Vitreous, pearly, or silky

Identified August 7, 2026More mineral →

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Physical properties

Formation & geological history

Forms in igneous rocks like granites and pegmatites, as well as in metamorphic rocks like schists and gneisses through regional metamorphism of argillaceous sediments.

Uses & applications

Used in electrical insulation, electronics, paints, plastics, joint cements, and as a pearlescent pigment in cosmetics.

Geological facts

Muscovite is also known commonly as common mica or potash mica. Historically, large sheets were used as a substitute for glass in stove doors and lanterns, particularly in Russia where it was called 'Muscovy glass'.

Field identification & locations

Easily identified by its perfect basal cleavage, allowing it to be peeled into thin, transparent, flexible sheets with a pearly luster. Found worldwide in pegmatite veins and metamorphic terranes.