mineral
Muscovite
Muscovite, KAl2(AlSi3O10)(OH)2
AI-generated identification · may be incorrectHardness: 2-2.5 on Mohs scale; Color: Colorless, silvery, white, grey, yellowish, brownish, or greenish; Luster: Vitreous, pearly, or silky; Crystal structure: Monoclinic, forms tabular crystals or sheet-like masses; Cleavage: Perfect basal cleavage yielding extremely thin, flexible elastic sheets;…
- Hardness
- 2-2
- Luster
- Vitreous, pearly, or silky
Identified More mineral →
Explore Muscovite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 2-2.5 on Mohs scale; Color: Colorless, silvery, white, grey, yellowish, brownish, or greenish; Luster: Vitreous, pearly, or silky; Crystal structure: Monoclinic, forms tabular crystals or sheet-like masses; Cleavage: Perfect basal cleavage yielding extremely thin, flexible elastic sheets; Specific gravity: 2.77-2.88
Formation & geological history
Forms in igneous rocks like granites and pegmatites, as well as in metamorphic rocks like schists and gneisses through regional metamorphism of argillaceous sediments.
Uses & applications
Used in electrical insulation, electronics, paints, plastics, joint cements, and as a pearlescent pigment in cosmetics.
Geological facts
Muscovite is also known commonly as common mica or potash mica. Historically, large sheets were used as a substitute for glass in stove doors and lanterns, particularly in Russia where it was called 'Muscovy glass'.
Field identification & locations
Easily identified by its perfect basal cleavage, allowing it to be peeled into thin, transparent, flexible sheets with a pearly luster. Found worldwide in pegmatite veins and metamorphic terranes.
