mineral

Tumbled or naturally etched mica-rich mineral specimen, likely muscovite

Muscovite, KAl₂(AlSi₃O₁₀)(OH)₂; possibly phlogopite mica

AI-generated identification · may be incorrect

Brownish translucent, pearly to vitreous luster with prominent sheet-like cleavage and flexible-looking lamellae; Mohs hardness 2–2.5, monoclinic crystal structure, and specific gravity about 2.8–3.1. The image suggests a mica crystal or mica-rich fragment rather than a conventional rock.

Identified August 10, 2026More mineral →

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Physical properties

Formation & geological history

Micas crystallize from cooling felsic igneous rocks, pegmatites, and metamorphic rocks such as schist and gneiss. They commonly formed during Precambrian to younger geological events, depending on the host deposit.

Uses & applications

Muscovite is used industrially in electrical insulation, joint compound, paints, plastics, and cosmetics; attractive crystals are collected but usually have modest gem value.

Geological facts

Its perfect basal cleavage allows it to split into extremely thin elastic sheets. Brown coloration may indicate iron-rich muscovite or phlogopite; exact identification requires chemical or optical testing.

Field identification & locations

Look for thin separable sheets, a pearly sheen, and light-colored transparent-to-brown flakes; mica commonly occurs with quartz and feldspar in pegmatites and schists. Estimated value: $2–$20 for a common hand specimen, up to $30–$100 for a large aesthetic crystal.