metamorphic

Likely serpentinite or serpentinized ultramafic rock

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

AI-generated identification · may be incorrect

Dark green-gray, mottled, fine-grained, and weakly waxy to dull in luster; commonly Mohs 2.5–4, with no obvious cleavage and irregular fracture. The rounded surface appears naturally weathered or waterworn, though the image cannot confirm exact mineralogy.

Identified September 15, 2026More metamorphic →

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At a glance

Common name: Likely serpentinite or serpentinized ultramafic rock
Scientific name: Serpentinite; chiefly serpentine-group minerals (Mg₃Si₂O₅(OH)₄), possibly with magnetite and minor olivine/pyroxene
Category: metamorphic
Identified: September 15, 2026
Method: Standard

AI Estimated Value

About $2–$20 for a common hand specimen; $25–$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 metamorphism, commonly along oceanic crust, faults, and subduction zones. Individual specimens may be geologically ancient, but age depends on the source body.

Uses & applications

Used as decorative stone, carving material, and occasionally aggregate; attractive varieties are collected, but it is not typically a gemstone.

Geological facts

Serpentinite commonly contains magnetite, giving some pieces a magnetic response and dark streaks. It may resemble jade, but is generally softer and less tough.

Field identification & locations

Common in ophiolites and tectonic belts, including California, Italy, New Zealand, and the Appalachian region. Check for a green streak, waxy feel, low hardness, and possible magnetism; definitive identification may require microscopy or chemical testing.