metamorphic

Tumbled greenish-gray stone, likely serpentinite or altered basalt

Probable serpentinite (serpentine-group minerals), possibly chlorite-/epidote-bearing basalt

AI-generated identification · may be incorrect

Typically Mohs 3–5.5; mottled olive-green, gray, and tan with a dull to waxy luster, fine-grained texture, and no visible crystal faces or cleavage. The rounded shape indicates tumbling or natural water wear.

Identified August 14, 2026More metamorphic →

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At a glance

Common name: Tumbled greenish-gray stone, likely serpentinite or altered basalt
Scientific name: Probable serpentinite (serpentine-group minerals), possibly chlorite-/epidote-bearing basalt
Category: metamorphic
Identified: August 14, 2026
Method: Standard

AI Estimated Value

About $2–$15 for a common tumbled stone; $20–$75 if unusually attractive, large, or confirmed as quality lapidary serpentinite.

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

Serpentinite forms when ultramafic mantle rocks are hydrated during metamorphism, commonly in oceanic crust and tectonic fault zones; altered basalt is a possible alternative. Exact age and identity cannot be determined from the photograph alone.

Uses & applications

Usually sold as a decorative or lapidary stone and used for carvings, cabochons, and polished objects; serpentinite has also been used as ornamental building stone.

Geological facts

The specimen appears to be a polished/tumbled geological material rather than a fresh unaltered rock. A hardness test, streak, specific gravity, and examination of a fresh surface would substantially improve identification.

Field identification & locations

Common serpentinite occurs in California, Vermont, Italy, New Zealand, and many ophiolite belts; it is identified by green mottling, waxy feel, and relatively low hardness. Avoid assuming it is jade without testing—serpentinite is softer and less dense.