mineral

Muscovite Mica

Muscovite - KAl2(AlSi3O10)(OH)2

Hardness: 2.5 on Mohs scale; Color: Colorless, silvery/grey to light brown; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect basal (peels in thin, flexible sheets); Specific gravity: 2.76–3.0

Hardness: 2
Color: Colorless, silvery/grey to light brown
Luster: Vitreous to pearly

Identified March 23, 2026More mineral →

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Physical properties

Formation & geological history

Formed through the cooling of silica-rich magma in pegmatites and granites, or through the regional metamorphism of clay-rich sedimentary rocks like shale. Found across various geological eras, notably in metamorphic belts.

Uses & applications

Used in the electronics industry as a high-heat insulator, in cosmetics (mica shimmer), and in joint compound and paint as a filler and stabilizer.

Geological facts

Also known as 'Muscovy Glass' because it was used in medieval Russia as a cheaper, more durable alternative to glass for windows. Its name is derived from the Muscovy province of Russia.

Field identification & locations

Identify in the field by its distinct ability to be peeled into transparent, flexible, elastic sheets with a fingernail. Found globally in granitic pegmatites and schist formations; collectors look for large, flat 'books' or crystals.