mineral

Polished dark stone, likely nephrite jade or serpentine

Tentatively nephrite (fibrous amphibole aggregate, Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂); possibly serpentine

AI-generated identification · may be incorrect

Small rounded, highly polished dark green-black specimen with waxy to vitreous luster and mottled green highlights. Nephrite has Mohs hardness 6–6.5, no visible cleavage, tough interlocking fibers, and specific gravity about 2.9–3.1; the photograph cannot confirm identity.

Identified September 3, 2026More mineral →

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At a glance

Common name: Polished dark stone, likely nephrite jade or serpentine
Scientific name: Tentatively nephrite (fibrous amphibole aggregate, Ca₂(Mg,Fe)₅Si₈O₂₂(OH)₂); possibly serpentine
Category: mineral
Identified: September 3, 2026
Method: Standard

AI Estimated Value

About $2–$20 for an unidentified tumbled stone; $20–$150+ if confirmed quality nephrite, with exceptional carvings far higher.

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

Nephrite forms through metamorphic alteration and metasomatism of ultramafic or calcium-rich rocks, commonly in serpentinite zones; deposits range from Paleozoic to younger. Serpentine forms by hydration of mantle-derived peridotite.

Uses & applications

Used for cabochons, beads, carvings, and ornamental objects; nephrite is valued for exceptional toughness, while ordinary serpentine is mainly decorative or architectural.

Geological facts

The dark color may result from iron-rich amphibole or magnetite inclusions. A polished surface obscures texture, so visual identification alone is provisional.

Field identification & locations

Check translucency, uniformity, heft, and a fibrous or interlocking texture under magnification; hardness and density testing, plus Raman or thin-section analysis, are more reliable. Common sources include British Columbia, Wyoming, New Zealand, China, and Russia.