mineral

Muscovite Mica

Muscovite (KAl2(AlSi3O10)(OH)2)

Hardness: 2.0-2.5; Color: Colorless, silvery-white, or tan; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect basal cleavage into thin, elastic sheets.

Hardness: 2
Color: Colorless, silvery-white, or tan
Luster: Vitreous to pearly

Identified April 3, 2026More mineral →

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Physical properties

Hardness: 2.0-2.5; Color: Colorless, silvery-white, or tan; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect basal cleavage into thin, elastic sheets.

Formation & geological history

Formed in igneous pegmatites and metamorphic rocks like schist and gneiss under high pressure and temperature conditions. It is a common rock-forming mineral found worldwide in ancient crustal formations.

Uses & applications

Used as an electrical insulator, in high-temperature furnaces, as a filler in paints and plastics, and in cosmetics (mica shimmer). High-quality translucent sheets were historically used for windows.

Geological facts

Also known as 'Muscovy glass' because it was used as a window material in medieval Russia. It is heat-resistant up to levels that would melt or shatter regular glass.

Field identification & locations

Identify by its ability to peel off into very thin, flexible, transparent layers with your fingernail. Commonly found in areas with exposed granite or metamorphic shields.