mineral

Muscovite Mica

Muscovite / KAl2(AlSi3O10)(OH)2

AI-generated identification · may be incorrect

Hardness: 2.5 on Mohs scale; Color: Colorless, silver-gray, or pale green; Luster: Vitreous to pearly; Crystal structure: Monoclinic; Cleavage: Perfect basal (peels into thin flexible sheets); Specific gravity: 2.82

Hardness: 2
Color: Colorless, silver-gray, or pale green
Luster: Vitreous to pearly

Identified March 22, 2026More mineral →

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Physical properties

Formation & geological history

Formed in igneous and metamorphic environments. Mostly found in pegmatites, granites, and regional metamorphic rocks like schist and phyllite. Geological age varies across eras depending on host rock formation.

Uses & applications

Used as an electrical insulator in electronics, a pearlescent pigment in makeup, a heat-resistant material for stove windows, and an additive in joint compound and paints.

Geological facts

Historically called 'Muscovy glass' because it was used as window panes in medieval Russia. It is highly elastic, meaning the sheets can be bent and will spring back to their original shape.

Field identification & locations

Identify in the field by its distinct 'books' of thin, transparent, flaky sheets that can be peeled with a fingernail. Commonly found in Brazil, India, and the United States (specifically North Carolina and South Dakota).