mineral

Mica (Biotite or Phlogopite Buchsam)

Silicate Mineral (Phyllosilicate family)

Hardness: 2.5–3.0 Mohs scale. Color: Dark brown, black, greyish-green, or smoky gray. Luster: Vitreous to pearly on cleavage surfaces. Crystal system: Monoclinic with perfect basal cleavage, peeling into thin flexible sheets. Specific gravity: 2.7–3.1.

Hardness: 2
Color: Dark brown, black, greyish-green, or smoky gray
Luster: Vitreous to pearly on cleavage surfaces

Identified July 24, 2026More mineral →

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Physical properties

Formation & geological history

Formed in metamorphic rocks such as schists and gneisses, as well as igneous rocks like granites and pegmatites. It crystallizes under high temperature and pressure conditions.

Uses & applications

Used in electrical insulation, cosmetics (glitter effect), drywall joint compound, filler in rubber and plastics, and as popular specimens for mineral collectors.

Geological facts

Mica crystals can peel into paper-thin, elastic sheets. Large mica crystals are colloquially called 'books' due to their layer-by-layer structure resembling book pages.

Field identification & locations

Look for a hexagonal or tabular crystal outline that easily flakes or peels into thin, shiny sheets. Commonly found in pegmatite deposits in Brazil, Russia, India, and the United States.

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Mineral

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Mineral/Rock