metamorphic

Serpentinized ultramafic rock (serpentinite)

Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, chromite, talc, and carbonate

AI-generated identification · may be incorrect

Typically green, gray, black, or mottled with waxy to greasy luster; Mohs hardness about 2.5–4, poor cleavage, massive or fibrous crystal texture, and specific gravity roughly 2.5–2.7. The image’s rounded, pale green mottling and dark veins are consistent with weathered serpentinite, though exact identification require…

Identified August 10, 2026More metamorphic →

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At a glance

Common name: Serpentinized ultramafic rock (serpentinite)
Scientific name: Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with possible magnetite, chromite, talc, and carbonate
Category: metamorphic
Identified: August 10, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common hand specimen; $30–$150 or more for attractive polished or carving-grade material.

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 during seafloor alteration or mountain-building, commonly along plate boundaries and fault zones. Formation ages vary widely, from Precambrian to modern tectonic settings.

Uses & applications

Used as decorative and architectural stone, carvings, aggregates, and historically as a source of asbestos-bearing material; gem-quality varieties may be polished as ornamental stone.

Geological facts

Serpentinite can contain magnetite and may be weakly magnetic; some varieties contain hazardous chrysotile asbestos. It is California’s state rock.

Field identification & locations

Common in ophiolites and tectonic mélanges, especially California, Italy, New Zealand, and parts of Canada. Field clues include a smooth waxy surface, green-black mottling, low hardness, and occasional magnetism; avoid cutting or sanding unknown specimens.