metamorphic

Serpentinite (serpentinized ultramafic rock)

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

AI-generated identification · may be incorrect

Usually dark green, gray, brown, or black with mottled, waxy to greasy luster; hardness about 2.5–5.5 Mohs, variable cleavage, and commonly a massive or mesh-textured crystal structure. This specimen’s green-gray color and strongly sheared, uneven surface are consistent with serpentinite, though photo identification is…

Identified September 22, 2026More metamorphic →

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At a glance

Common name: Serpentinite (serpentinized ultramafic rock)
Scientific name: Serpentinite; chiefly serpentine-group minerals (antigorite, lizardite, chrysotile), with possible magnetite, olivine, pyroxene, and talc
Category: metamorphic
Identified: September 22, 2026
Method: Standard

AI Estimated Value

About $10–$50 for a common hand specimen; $50–$200+ for attractive polished, patterned, or locality-labeled 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 metamorphosed by water, commonly along oceanic crust and subduction-zone faults. It may range from Paleozoic to recent tectonic settings, depending on the exposure.

Uses & applications

Used as decorative stone, carvings, countertops, and historically as asbestos-bearing material; quality specimens are collected rather than typically used as aggregate because chrysotile may occur.

Geological facts

Often associated with chromite, magnetite, talc, and nickel deposits; some pieces are weakly magnetic. Avoid cutting or sanding unknown material because fibrous chrysotile asbestos may be present.

Field identification & locations

Common in ophiolites and tectonic belts, including California, Vermont, Quebec, Italy, New Zealand, and Oman. Field clues include green-black mottling, waxy surfaces, slickensides, and relatively low hardness.