metamorphic

Tumbled dark olive stone, likely serpentinite or greenstone

Probable serpentinite, dominated by antigorite/lizardite minerals; exact identification requires testing

AI-generated identification · may be incorrect

Mohs hardness commonly 2.5–4; opaque olive-brown to dark green, waxy to dull luster, fine-grained and massive with no visible crystals or cleavage. The smooth surface indicates natural water-wear or tumbling.

Identified August 26, 2026More metamorphic →

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At a glance

Common name: Tumbled dark olive stone, likely serpentinite or greenstone
Scientific name: Probable serpentinite, dominated by antigorite/lizardite minerals; exact identification requires testing
Category: metamorphic
Identified: August 26, 2026
Method: Standard

AI Estimated Value

$2–$15 as a common tumbled stone; up to $20–$50 if attractively patterned, authenticated, or unusually large.

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

Serpentinite forms when ultramafic mantle rocks, especially peridotite, hydrate during hydrothermal alteration, commonly along plate boundaries and ophiolites; ages vary widely. A greenstone alternative could include metamorphosed basalt or other mafic rock.

Uses & applications

Used as a carving and ornamental stone, lapidary material, aggregate, and occasionally architectural stone; this piece has modest decorative or educational value.

Geological facts

Serpentinite’s green color comes from hydrated magnesium silicates and may be mottled by magnetite or carbonate veins. Some varieties contain chrysotile asbestos, so avoid cutting or generating dust unless tested.

Field identification & locations

Look for a greasy/waxy feel, low density, olive-green color, dark veining, and occasional magnetism; hardness and streak tests help distinguish it from jade. Common sources include California, Italy, New Zealand, Canada, and ophiolite belts worldwide.