metamorphic

Weathered greenish-brown rock, likely serpentinized ultramafic rock

Serpentinite; chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), possibly with olivine, pyroxene, magnetite, or carbonate

AI-generated identification · may be incorrect

Typically dark green to brown, mottled, and waxy to dull; hardness about 2.5–4 Mohs, uneven fracture, and variable density. The specimen appears fine-grained and weathered, but image-based identification is tentative.

Identified September 4, 2026More metamorphic →

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At a glance

Common name: Weathered greenish-brown rock, likely serpentinized ultramafic rock
Scientific name: Serpentinite; chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), possibly with olivine, pyroxene, magnetite, or carbonate
Category: metamorphic
Identified: September 4, 2026
Method: Standard

AI Estimated Value

$2–$15 for a small common specimen; $20–$100+ if exceptionally patterned, polished, or from a documented locality.

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

Forms when mantle-derived peridotite is hydrated and altered by low-temperature metamorphism, commonly along oceanic crust and tectonic plate boundaries. Serpentinite may range from Paleozoic to modern tectonic settings.

Uses & applications

Used as ornamental stone, carvings, landscaping material, and occasionally dimension stone; associated chromite and nickel deposits can have industrial importance.

Geological facts

Serpentinite commonly contains magnetite, making some pieces weakly magnetic. Its green color and slick or waxy surfaces distinguish it from many ordinary sedimentary rocks.

Field identification & locations

Look for a green mottled color, unusually smooth or soapy feel, low hardness, and possible magnetism; confirm with a streak, hardness, and mineralogical test. Common in ophiolite belts and subduction zones worldwide.