metamorphic

Mica schist (likely biotite-rich schist)

Mica schist, dominated by biotite mica (K(Mg,Fe)₃AlSi₃O₁₀(F,OH)₂), with possible quartz and feldspar

AI-generated identification · may be incorrect

Hardness about 2.5–3 for mica and 6–7 for quartz; brown-gold, strongly foliated, platy, with vitreous to pearly luster and perfect basal cleavage. The specimen appears flaky and sparkly, though lighting and processing make exact identification uncertain.

Identified September 13, 2026More metamorphic →

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At a glance

Common name: Mica schist (likely biotite-rich schist)
Scientific name: Mica schist, dominated by biotite mica (K(Mg,Fe)₃AlSi₃O₁₀(F,OH)₂), with possible quartz and feldspar
Category: metamorphic
Identified: September 13, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common hand specimen; larger, unusually attractive or locality-labeled pieces may sell for $30–$100.

Not an official valuation

AI estimate for general interest only — not an appraisal. Actual value depends on condition, provenance, and market demand. Verify with a professional before buying, selling, or insuring.

This identification was generated by AI and may contain errors. Verify important details before relying on them — and never use an AI result to judge whether a specimen is safe to handle. Read the full disclaimer

Physical properties

Formation & geological history

Formed when shale or another clay-rich sediment was subjected to elevated temperature and pressure during regional metamorphism, commonly during mountain building. Its exact geological age cannot be determined from the image.

Uses & applications

Used mainly as a decorative stone, teaching specimen, and collector material; mica may have industrial uses as an electrical and thermal insulator, but this rough piece is unlikely to be commercially useful.

Geological facts

The glittering layers are aligned mica flakes that produce schistosity; individual sheets can split into thin elastic flakes. Gold-brown coloration commonly reflects iron-rich biotite or weathered mica.

Field identification & locations

Identify it by its pronounced layered fabric, flexible cleavage flakes, and glittering platy surfaces; mica schists occur widely in metamorphic mountain belts. A hand lens, streak, hardness, and thin-section examination would distinguish it from mica-rich pegmatite or phyllite.