metamorphic

Serpentinite pebble

Serpentinite, composed mainly of serpentine-group minerals (commonly antigorite, lizardite, or chrysotile)

AI-generated identification · may be incorrect

Fine-grained, rounded gray-green stone with a waxy to slightly silky luster and dark veining. Serpentine minerals have Mohs hardness of about 2.5–5.5; crystal structure and cleavage vary by mineral, so a photo alone cannot establish exact composition or specific gravity.

Identified September 28, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when water alters ultramafic rocks, especially peridotite, during hydrothermal alteration or metamorphism; this specimen’s age and source cannot be determined from the image.

Uses & applications

Serpentinite is used as decorative stone, carving material, and occasionally dimension stone; small pebbles are primarily collected or used in landscaping.

Geological facts

The name refers to its often mottled, snake-skin-like appearance; some serpentinite contains fibrous chrysotile asbestos, so avoid cutting or grinding unidentified material.

Field identification & locations

Look for a dense, smooth green-gray stone with waxy sheen and veins or mottling; serpentinite occurs in ultramafic and ophiolite belts worldwide. The rounded form suggests transport by water, but does not identify its locality.