metamorphic

Likely serpentine-rich ultramafic rock

Serpentinite; chiefly serpentine-group minerals (Mg3Si2O5(OH)4), commonly with magnetite and relict olivine/pyroxene

AI-generated identification · may be incorrect

Dark olive-green to brown, waxy or greasy luster, massive and fine-grained; Mohs hardness about 2.5–4, with no obvious cleavage. The rounded, glossy surface appears water-worn or polished, so texture and exact mineralogy cannot be confirmed from the image alone.

Identified September 21, 2026More metamorphic →

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At a glance

Common name: Likely serpentine-rich ultramafic rock
Scientific name: Serpentinite; chiefly serpentine-group minerals (Mg3Si2O5(OH)4), commonly with magnetite and relict olivine/pyroxene
Category: metamorphic
Identified: September 21, 2026
Method: Standard

AI Estimated Value

Typically $5–$30 for a common water-worn specimen; $30–$100+ for unusually attractive, polished, or well-documented pieces.

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 hydrothermal fluids, commonly along faults and tectonic plate boundaries. Serpentinization occurs from the Precambrian to the present.

Uses & applications

Used as decorative stone, carving material, aggregate, and historically as a source of asbestos-bearing minerals; attractive pieces may be collected as lapidary specimens.

Geological facts

Serpentinite is often strongly magnetic if magnetite-rich and may contain fibrous chrysotile asbestos, so avoid cutting, grinding, or generating dust. Its green color commonly results from serpentine minerals.

Field identification & locations

Look for olive-green color, waxy feel, low hardness, curved veining, and possible magnetism; common in ophiolites and metamorphic belts worldwide, including California, Italy, New Zealand, and the Canadian Rockies.