metamorphic

Serpentinite (likely serpentinized ultramafic rock)

Serpentinite; chiefly serpentine-group minerals (antigorite, lizardite, chrysotile), with possible magnetite, olivine, pyroxene, and talc

AI-generated identification · may be incorrect

Dark green-black, mottled and locally rusty orange; commonly waxy to greasy luster, fine-grained, and massive, with Mohs hardness about 2.5–4 and no prominent cleavage. The specimen appears weathered and mixed with lighter quartz/feldspar-bearing material, so exact identification is uncertain from the image alone.

Identified September 12, 2026More metamorphic →

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At a glance

Common name: Serpentinite (likely serpentinized ultramafic rock)
Scientific name: Serpentinite; chiefly serpentine-group minerals (antigorite, lizardite, chrysotile), with possible magnetite, olivine, pyroxene, and talc
Category: metamorphic
Identified: September 12, 2026
Method: Standard

AI Estimated Value

Typically $2–$20 for an ordinary hand specimen; attractive polished or patterned pieces may sell for $25–$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

Forms when mantle-derived peridotite is hydrated and metamorphosed by water, commonly along faults and mid-ocean ridges; many exposures range from Paleozoic to Mesozoic or younger. Orange-brown surfaces reflect oxidation of iron-bearing minerals.

Uses & applications

Used as decorative stone, sculpture, aggregate, and historically as a source of asbestos where chrysotile is present; it is generally unsuitable for casual cutting or dust production without testing.

Geological facts

Serpentinite often has a distinctive slick, waxy appearance and may be weakly magnetic from magnetite. Some varieties contain chromium, nickel, and asbestos minerals.

Field identification & locations

Look for green-black color, greasy/waxy texture, soft scratch response, and possible magnetism; acid testing is usually negative. Common in California, the Appalachians, the Alps, New Zealand, and ophiolite belts worldwide.