mineral

Muscovite

KAl2(AlSi3O10)(OH)2

Hardness: 2 to 2.5 on Mohs scale; Color: Yellow, silvery, white, brownish, or green; Luster: Vitreous, pearly, or silky; Crystal Structure: Monoclinic, typically forming tabular crystals or micaceous sheets with perfect basal cleavage; Specific Gravity: 2.76 to 3.0

Hardness: 2 to 2
Color: Yellow, silvery, white, brownish, or green
Luster: Vitreous, pearly, or silky

Identified August 3, 2026More mineral →

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Physical properties

Formation & geological history

Forms in granitic pegmatites, metamorphic rocks like schists and gneisses, and as a detrital mineral in sedimentary rocks through regional metamorphism or igneous crystallization.

Uses & applications

Used in electrical insulation, paints, plastics, joint compounds, and as a pearlescent pigment in cosmetics, though rare large sheets historically served as window glass.

Geological facts

Muscovite is the most common member of the mica group. Its name comes from 'Muscovy-glass', a term used in Elizabethan England for the mineral imported from Russia for use in windows.

Field identification & locations

Easily identified by its extremely perfect cleavage, allowing it to be split into flexible, elastic, and transparent sheets. Commonly found in pegmatite dikes and metamorphic terrains worldwide.