metamorphic

Tumbled greenstone, likely serpentine or altered jade-like rock

Serpentinite (predominantly serpentine-group minerals; Mg₃Si₂O₅(OH)₄), possibly nephrite jade if notably tough and dense

AI-generated identification · may be incorrect

Pale green, mottled, smooth tumbled surface with dull-to-waxy luster; typically Mohs 2.5–5.5 for serpentine and 6–6.5 for nephrite. Fine-grained and massive, without visible cleavage; specific gravity is roughly 2.5–3.0.

Identified September 2, 2026More metamorphic →

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At a glance

Common name: Tumbled greenstone, likely serpentine or altered jade-like rock
Scientific name: Serpentinite (predominantly serpentine-group minerals; Mg₃Si₂O₅(OH)₄), possibly nephrite jade if notably tough and dense
Category: metamorphic
Identified: September 2, 2026
Method: Standard

AI Estimated Value

About $2–$15 for a common tumbled stone; approximately $20–$100+ if confirmed as attractive, high-quality 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 forms when ultramafic mantle rocks hydrate during metamorphism, commonly in oceanic crust and subduction-zone mélanges; the specimen’s exact age cannot be determined visually.

Uses & applications

Commonly sold as a decorative, polished, or worry stone; higher-quality nephrite is used for carvings and jewelry, while serpentinite has limited architectural and ornamental use.

Geological facts

The appearance alone cannot reliably distinguish serpentine from jade, green quartzite, or other altered rocks; hardness, density, translucency, and laboratory testing are useful.

Field identification & locations

Common sources include California, New Zealand, British Columbia, Russia, and Afghanistan. A steel scratch test, specific-gravity measurement, and professional gemological testing can help identify it; avoid acid testing.