mineral

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(F,OH)2)

Hardness: 2-2.5; Color: Silver, white, or colorless; Luster: Pearly to metallic; Crystal Structure: Monoclinic; Cleavage: Perfect basal (peels into thin sheets); Specific Gravity: 2.76-3.00

Hardness: 2-2
Color: Silver, white, or colorless
Luster: Pearly to metallic

Identified May 25, 2026More mineral →

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Physical properties

Hardness: 2-2.5; Color: Silver, white, or colorless; Luster: Pearly to metallic; Crystal Structure: Monoclinic; Cleavage: Perfect basal (peels into thin sheets); Specific Gravity: 2.76-3.00

Formation & geological history

Formed primarily in granitic pegmatites, metamorphic rocks like schists and gneisses, and occasionally in hydrothermal veins. It develops through the cooling of magma or the metamorphism of clay-rich sediments.

Uses & applications

Used as an electrical insulator in electronics, as a filler in paints and plastics, in joint compound for drywall, and in cosmetics for its shimmer. Collectors value large, well-formed 'books' or crystals.

Geological facts

Historically called 'Muscovy glass' because it was used as a cheaper, heat-resistant alternative to glass for windows in Russia. It is one of the most common members of the mica group.

Field identification & locations

Identified in the field by its metallic luster and ability to be peeled into thin, flexible, transparent sheets using a fingernail or knife. Commonly found in pegmatite deposits worldwide.