metamorphic

Likely biotite-rich mica schist

Mica schist, chiefly biotite (K(Mg,Fe)₃AlSi₃O₁₀(F,OH)₂); exact identification from image is uncertain

AI-generated identification · may be incorrect

Dark brown to black, shiny platy layers and strong foliation; mica has Mohs hardness 2–3, perfect basal cleavage, and a monoclinic crystal structure. The specimen appears rough and flaky rather than glassy or metallic.

Identified September 25, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed when clay-rich sedimentary or volcanic rock underwent regional metamorphism, aligning mica into layers; age depends on its source locality and cannot be determined visually.

Uses & applications

Mica schist is mainly a collecting and decorative stone; mica has industrial uses as an electrical and thermal insulator, while schist may be used as building or landscaping stone.

Geological facts

Its glittering sheets reflect light from mica’s layered structure. A protruding metallic-looking feature may be an attached object or inclusion, not enough to identify the rock by itself.

Field identification & locations

Look for thin, shiny flakes and pronounced parallel foliation; biotite schist occurs in metamorphic belts worldwide. Confirm by testing cleavage and examining a fresh surface.