metamorphic

Tumbled gray-green stone, likely serpentinite or chlorite-rich metamorphic rock

Serpentinite (predominantly serpentine-group minerals: antigorite, lizardite, or chrysotile); identification is provisional from the photograph

AI-generated identification · may be incorrect

Dark gray-green, fine-grained, dull to subtly waxy luster, with no visible crystals or cleavage; typical hardness is 2.5–4 Mohs and specific gravity about 2.5–2.6. The rounded shape indicates natural water wear or tumbling/polishing.

Identified September 13, 2026More metamorphic →

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At a glance

Common name: Tumbled gray-green stone, likely serpentinite or chlorite-rich metamorphic rock
Scientific name: Serpentinite (predominantly serpentine-group minerals: antigorite, lizardite, or chrysotile); identification is provisional from the photograph
Category: metamorphic
Identified: September 13, 2026
Method: Standard

AI Estimated Value

About $2–$15 for a small common tumbled specimen; $20–$75 for attractive polished material or unusual patterns.

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

Usually forms when ultramafic mantle rocks such as peridotite undergo hydration and metamorphism, commonly along tectonic plate boundaries; formation ages vary widely from Precambrian to recent tectonic settings.

Uses & applications

Used as ornamental stone, carvings, beads, and sometimes architectural facing; softer pieces are popular as inexpensive lapidary material.

Geological facts

Serpentinite commonly contains magnetite and may show a mottled, fibrous, or slick appearance. Some specimens can contain asbestos-form minerals, so avoid cutting or generating dust unless composition is confirmed.

Field identification & locations

Common in ophiolites and subduction-zone belts, including California, Italy, New Zealand, and Canada. A streak, hardness test, waxy feel, and close inspection for green veining would help distinguish it from graywacke, basalt, or slate.