metamorphic

Polished greenstone (likely serpentine or nephrite jade)

Serpentine-group mineral aggregate, commonly antigorite/lizardite; possible nephrite, a tremolite–actinolite amphibole aggregate

AI-generated identification · may be incorrect

Dark olive-green, fine-grained, waxy to subvitreous luster, with a natural vein or fracture. Serpentine has Mohs hardness 2.5–4; nephrite is tougher and harder, about 6–6.5; nontransparent and commonly massive rather than visibly crystalline.

Identified September 21, 2026More metamorphic →

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At a glance

Common name: Polished greenstone (likely serpentine or nephrite jade)
Scientific name: Serpentine-group mineral aggregate, commonly antigorite/lizardite; possible nephrite, a tremolite–actinolite amphibole aggregate
Category: metamorphic
Identified: September 21, 2026
Method: Standard

AI Estimated Value

About $5–$25 as a common polished serpentine piece; approximately $20–$150+ if confirmed as attractive, high-quality nephrite.

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

Formed by hydrothermal alteration of ultramafic rocks, or by metamorphism producing amphibole-rich nephrite. Most examples are Paleozoic or younger, though the specimen’s exact age cannot be determined visually.

Uses & applications

Used as a tumbled ornamental stone, carving material, and occasionally jewelry; nephrite-quality material has greater gem value, while ordinary serpentine is mainly decorative.

Geological facts

The rounded shape and glossy surface indicate human tumbling or polishing. The long pale seam is likely a contrasting mineral vein or healed fracture.

Field identification & locations

Common sources include New Zealand, British Columbia, California, Wyoming, Russia, China, and Afghanistan. Check hardness, toughness, density, and translucency; a laboratory test is needed to distinguish serpentine from nephrite reliably.