mineral

Muscovite Mica

Muscovite [KAl2(AlSi3O10)(OH)2]

Hardness: 2-2.5; Color: Colorless, silvery, or light brown; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect basal cleavage (peels into thin sheets); Specific gravity: 2.76-3.0

Hardness: 2-2
Color: Colorless, silvery, or light brown
Luster: Vitreous to pearly

Identified June 28, 2026More mineral →

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Physical properties

Formation & geological history

Formed in igneous environments (pegmatites and granites) and metamorphic rocks (schists and gneisses). It crystallizes from magma or forms through the alteration of other minerals during metamorphism.

Uses & applications

Used as an electrical and thermal insulator in electronics, as a filler in paints and plastics, and in cosmetics (mica powder) for its pearlescent shimmer. Historically used as window panes.

Geological facts

Also known as 'Muscovy glass' because it was used in medieval Russia as a cheap alternative to glass for windows. It is highly heat-resistant and does not conduct electricity.

Field identification & locations

Identify by its 'book' like structure and the ability to peel off elastic, transparent sheets with a fingernail. Commonly found in large flakes within granite pegmatites.