metamorphic

Tumbled serpentine (likely)

Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄

AI-generated identification · may be incorrect

Olive-green to yellow-green, mottled and waxy to greasy luster, with a smooth polished surface; typically Mohs 2.5–4, opaque, and massive rather than visibly crystalline. The rounded form indicates tumbling or natural water wear.

Identified September 21, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when ultramafic mantle rocks such as peridotite undergo hydration and metamorphic alteration, commonly in ophiolites and subduction-related zones. Serpentinization is generally Mesozoic to recent depending on the host body.

Uses & applications

Used as a decorative and ornamental stone, carving material, tumbled stone, and occasionally as dimension stone; attractive pieces are collected but are usually modestly priced.

Geological facts

The image is consistent with serpentine or serpentinite, though similar olive-green rocks such as nephrite, jasper, or altered basalt can look comparable. Serpentine may contain minor magnetite, chromite, and relic pyroxene.

Field identification & locations

Common sources include California, Italy, New Zealand, Canada, and the Ural Mountains. Identify it by its low hardness, green mottling, waxy feel, and tendency to scratch with a steel knife; definitive identification requires testing or microscopy.