metamorphic

Likely serpentinite (serpentine-rich metamorphic rock)

Serpentinite, chiefly serpentine-group minerals (chrysotile, lizardite, antigorite), commonly with magnetite and minor talc/carbonate

AI-generated identification · may be incorrect

Dark gray-green, mottled and subtly veined, with a waxy to dull luster and fine-grained texture. Typical hardness is about 2.5–4 Mohs; cleavage is poor or absent, and density is usually 2.5–2.6. The photograph does not clearly show diagnostic crystals.

Identified September 1, 2026More metamorphic →

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At a glance

Common name: Likely serpentinite (serpentine-rich metamorphic rock)
Scientific name: Serpentinite, chiefly serpentine-group minerals (chrysotile, lizardite, antigorite), commonly with magnetite and minor talc/carbonate
Category: metamorphic
Identified: September 1, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common rough hand specimen; $30–$150+ for attractive polished or patterned 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 ultramafic mantle rocks such as peridotite hydrate during metamorphism, commonly along faults and subduction zones. Serpentinization can occur from the Precambrian to the present, so age requires locality information.

Uses & applications

Used as decorative stone, carvings, countertops, and occasionally jewelry; historically used as a source of asbestos-bearing material. Avoid cutting or sanding unknown specimens because some serpentinite contains fibrous chrysotile.

Geological facts

Its green color results from hydration and alteration of olivine- and pyroxene-rich rocks. Magnetite produced during serpentinization may make pieces weakly magnetic.

Field identification & locations

Look for green-black mottling, slick or waxy surfaces, veining, and unusually low hardness; a steel nail may scratch it. Common in ophiolites and tectonic belts worldwide, including Oman, California, Italy, New Zealand, and Greece.