metamorphic
Likely biotite-rich mica schist
Mica schist, chiefly biotite (K(Mg,Fe)₃AlSi₃O₁₀(OH,F)₂) with possible quartz and feldspar
AI-generated identification · may be incorrectBrown, flaky and foliated with a lustrous, layered surface; biotite hardness 2.5–3, with perfect basal cleavage. The photo is insufficient to confirm mineral composition or distinguish schist from a mica-rich specimen.
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Physical properties
Brown, flaky and foliated with a lustrous, layered surface; biotite hardness 2.5–3, with perfect basal cleavage. The photo is insufficient to confirm mineral composition or distinguish schist from a mica-rich specimen.
Formation & geological history
Forms when clay-rich or other fine-grained rocks undergo heat and pressure, aligning mica into visible foliation. Metamorphic age varies by locality and cannot be determined from appearance alone.
Uses & applications
Schist is used as decorative or landscaping stone and as a teaching or collecting specimen; mica has industrial uses as an electrical and thermal insulator.
Geological facts
Mica splits into thin, flexible sheets, and its aligned flakes give schist its characteristic sheen and layered texture.
Field identification & locations
Look for abundant visible mica flakes and a tendency to split along foliation; confirm with close inspection because the pictured fragment may be another mica-rich rock. Mica schists occur in metamorphic belts worldwide.
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