metamorphic

Banded metamorphic rock, likely mica schist or gneiss

Quartz–feldspar–mica schist/gneiss; exact identification requires a fresh surface and mineral tests

AI-generated identification · may be incorrect

Gray-brown, strongly foliated and layered, with visible silvery mica, quartz, and feldspar; likely Mohs 5–7, vitreous to pearly luster, and moderate-to-good foliation with mica cleavage. The rounded shape indicates abrasion or stream/beach transport.

Identified August 8, 2026More metamorphic →

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At a glance

Common name: Banded metamorphic rock, likely mica schist or gneiss
Scientific name: Quartz–feldspar–mica schist/gneiss; exact identification requires a fresh surface and mineral tests
Category: metamorphic
Identified: August 8, 2026
Method: Standard

AI Estimated Value

About $1–$10 for a common hand specimen; $10–$30 if unusually attractive, polished, or provenance-documented.

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 clay-rich or granitic protoliths underwent high-temperature and pressure metamorphism, aligning mica and segregating minerals into bands. Such rocks commonly formed during ancient mountain-building events, often Precambrian to Paleozoic in age.

Uses & applications

Used locally as decorative stone, aggregate, landscaping rock, and occasionally thin architectural slabs; generally not a gemstone-quality material.

Geological facts

The planar mineral alignment causes it to split preferentially along foliation, while quartz-rich layers resist weathering and stand out in relief.

Field identification & locations

Look for continuous foliation, sparkly mica flakes, and alternating light/dark mineral bands; distinguish from slate by its coarser grains and from granite by its planar fabric. Common in metamorphic mountain belts and glacial or beach gravels.