metamorphic

Weathered quartz-rich metamorphic rock, likely gneiss

Quartz–feldspar–mica gneiss; exact identification requires thin-section or chemical testing

AI-generated identification · may be incorrect

Coarse, irregularly banded texture with tan, white, gray, and dark brown mineral zones; likely quartz and feldspar with biotite or iron-oxide staining. Hardness about 6–7, generally nonmetallic with vitreous to dull luster, weak foliation, and no obvious cleavage on the broken surface.

Identified September 13, 2026More metamorphic →

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At a glance

Common name: Weathered quartz-rich metamorphic rock, likely gneiss
Scientific name: Quartz–feldspar–mica gneiss; exact identification requires thin-section or chemical testing
Category: metamorphic
Identified: September 13, 2026
Method: Standard

AI Estimated Value

Approximately $5–$25 as an ordinary hand specimen; potentially $30–$100 if unusually attractive, locality-labeled, or display-sized.

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 preexisting quartz- and feldspar-rich rock underwent high-grade metamorphism, producing mineral segregation and banding; commonly Precambrian to Paleozoic in age. Surface oxidation and weathering account for the rusty brown colors.

Uses & applications

Used as crushed stone, aggregate, building or landscaping stone, and occasionally as a decorative specimen; the irregular weathering makes it less suitable for high-quality polished slabs.

Geological facts

The image suggests gneiss but could also represent strongly weathered granite or a quartz-rich breccia; visual identification alone cannot establish the exact rock name.

Field identification & locations

Look for alternating light quartz/feldspar and dark mica-rich bands, hard grains, and resistance to scratching by a steel knife. Common in continental mountain belts and exposed Precambrian shields worldwide.