metamorphic

Tumbled serpentine (likely green serpentinite)

Serpentine-group minerals, commonly antigorite, lizardite, or chrysotile; serpentinite is the rock

AI-generated identification · may be incorrect

Dark green to pale green with black streaks and a polished, waxy-to-greasy luster. Serpentine minerals are typically Mohs 2.5–5.5, with fine-grained, interlocking or fibrous textures; exact hardness and composition cannot be confirmed from the image.

Identified October 13, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when magnesium-rich ultramafic rocks are altered by water during serpentinization, commonly along oceanic crust and tectonic plate boundaries. The process can occur at many geological ages.

Uses & applications

Polished serpentine is used for carvings, beads, and decorative stone; serpentinite is also used as dimension stone and, historically, as a source of asbestos where chrysotile is present.

Geological facts

Serpentine is a mineral group rather than a single mineral, and serpentinite is its rock counterpart. The specimen’s rounded shape and shine suggest tumbling or polishing.

Field identification & locations

The green-and-black color and smooth, waxy appearance are consistent with serpentine, but visual identification is not definitive. Serpentinite occurs in many mountain belts and ophiolites worldwide; avoid cutting or grinding unidentified material because some serpentinite contains chrysotile asbestos.