metamorphic

Polished dark green stone, likely serpentinite or chlorite schist

Serpentinite (Mg-rich serpentine minerals, commonly antigorite/lizardite) or chlorite-rich schist

AI-generated identification · may be incorrect

Dark green to black, fine-grained, waxy-to-submetallic luster with pale reflective flecks; typically Mohs 2.5–4 for serpentinite (chlorite schist about 2–3), massive or weakly foliated, with no obvious cleavage visible. The rounded shape indicates tumbling or polishing.

Identified September 14, 2026More metamorphic →

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At a glance

Common name: Polished dark green stone, likely serpentinite or chlorite schist
Scientific name: Serpentinite (Mg-rich serpentine minerals, commonly antigorite/lizardite) or chlorite-rich schist
Category: metamorphic
Identified: September 14, 2026
Method: Standard

AI Estimated Value

About $2–$15 for a common tumbled piece; $20–$75 if unusually attractive, large, or confidently identified.

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

Forms when ultramafic mantle rocks such as peridotite undergo hydration and metamorphism, commonly in ancient oceanic crust and tectonic suture zones; individual pieces may range from Precambrian to much younger. Exact identification and age require testing or microscopy.

Uses & applications

Used as ornamental stone, carvings, counters, and collectible tumbled material; some serpentinite is marketed as “new jade,” though it is not jadeite or nephrite. Common pieces generally have modest commercial value.

Geological facts

Serpentinite often shows a greasy or waxy surface and may contain magnetite, producing dark specks or slight magnetism. Chlorite-rich rocks can look similar but are usually more distinctly flaky or schistose.

Field identification & locations

Check for a waxy feel, green-black color, soft scratchability with a steel nail, and possible magnetism; avoid acid-based identification. Common localities include California, Italy, New Zealand, Canada, and tectonic mountain belts worldwide.