metamorphic

Tumbled dark green stone, likely serpentine

Serpentine-group minerals, chiefly antigorite/lizardite (approximately Mg₃Si₂O₅(OH)₄)

AI-generated identification · may be incorrect

Dark green to nearly black, polished vitreous-to-waxy luster, fine-grained and opaque with mottled patches. Mohs hardness is about 2.5–4; cleavage is poor to absent, and specific gravity is roughly 2.5–2.6.

Identified September 2, 2026More metamorphic →

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At a glance

Common name: Tumbled dark green stone, likely serpentine
Scientific name: Serpentine-group minerals, chiefly antigorite/lizardite (approximately Mg₃Si₂O₅(OH)₄)
Category: metamorphic
Identified: September 2, 2026
Method: Standard

AI Estimated Value

Approximately $2–$15 for a common tumbled piece; $20–$100+ for larger, attractive, or gem-quality serpentine carvings.

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

Serpentine forms when ultramafic mantle rocks such as peridotite are hydrated during metamorphism, commonly in oceanic crust and subduction-zone settings. The pictured piece is tumbled and polished, so original textures are obscured; age depends on its source rock.

Uses & applications

Used as an ornamental stone, carvings, beads, cabochons, and decorative objects; massive serpentine has also been used historically in architecture. It is generally inexpensive as a tumbled stone.

Geological facts

Its dark green color can resemble nephrite jade, but serpentine is much softer and commonly shows waxy polish and mottled veining. Some varieties may contain chrysotile asbestos, so avoid cutting, drilling, or generating dust unless composition is confirmed.

Field identification & locations

Common sources include California, New Zealand, Italy, Canada, Russia, and Afghanistan. Field confirmation requires hardness, streak, density, and ideally microscopy or X-ray analysis; visual identification is provisional from this photograph.