metamorphic

Possibly biotite-rich schist

Mica schist, composed mainly of quartz and mica (often biotite); exact identification is uncertain from the photo.

AI-generated identification · may be incorrect

Dark gray-brown, coarse and visibly glittery with flaky mica; likely Mohs 2–3 for the mica and 7 for quartz. Schistose texture; mineral grains and cleavage are difficult to confirm from this view.

Identified October 4, 2026More metamorphic →

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Physical properties

Dark gray-brown, coarse and visibly glittery with flaky mica; likely Mohs 2–3 for the mica and 7 for quartz. Schistose texture; mineral grains and cleavage are difficult to confirm from this view.

Formation & geological history

Formed when clay-rich sedimentary rock was buried and recrystallized under heat and pressure. Such rocks formed in many geological periods; the specimen’s age cannot be determined visually.

Uses & applications

Schist is used as a decorative building or landscaping stone and collected as a field specimen; mica has industrial uses as an insulating and filler material.

Geological facts

The shimmering flecks are consistent with mica, whose platy crystals reflect light and commonly give schist its characteristic sheen.

Field identification & locations

Look for aligned, glittering flakes and a tendency to split along them; quartz-rich grains may feel hard and resist scratching. Mica schists occur in metamorphic mountain belts worldwide.