metamorphic

Tumbled greenstone / serpentine

Serpentine-group rock, chiefly antigorite/lizardite; possibly nephrite jade or chlorite-rich greenstone

AI-generated identification · may be incorrect

Olive-green, opaque, rounded and polished, with waxy to greasy luster and mottled texture. Serpentine hardness is about 2.5–4 Mohs; nephrite, if confirmed, is tougher and about 6–6.5 Mohs; specific gravity is roughly 2.5–3.0.

Identified September 21, 2026More metamorphic →

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At a glance

Common name: Tumbled greenstone / serpentine
Scientific name: Serpentine-group rock, chiefly antigorite/lizardite; possibly nephrite jade or chlorite-rich greenstone
Category: metamorphic
Identified: September 21, 2026
Method: Standard

AI Estimated Value

About $5–$30 for a common tumbled serpentine/greenstone piece; $50–$300 or more if laboratory-confirmed as attractive nephrite jade.

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 formed when ultramafic mantle rocks hydrate during metamorphism, commonly in ophiolites and subduction zones. The photograph alone cannot establish a geological age; formation may range from Paleozoic to recent tectonic settings.

Uses & applications

Used as ornamental stone, carvings, cabochons, countertops, and occasionally as a jade substitute; nephrite-quality material is used in jewelry and art objects.

Geological facts

The smooth green appearance is characteristic of serpentine-family material, but visual identification cannot reliably distinguish it from nephrite, chlorite, or other greenstones.

Field identification & locations

Commonly found in serpentinite belts worldwide, including California, New Zealand, Italy, Canada, and China. Field tests include a streak test, hardness testing, and checking for fibrous or greasy texture; avoid acid and destructive tests on valuable pieces.