metamorphic

Rounded greenstone pebble

Likely serpentinite or chlorite-rich metamorphic rock; exact identification requires testing

AI-generated identification · may be incorrect

Olive-green to yellow-green, opaque, smooth water-worn surface, and dull to subtly waxy luster. Likely Mohs hardness 2.5–4; massive, fine-grained, with no visible cleavage or crystals; composition may include serpentine, chlorite, epidote, and magnetite.

Identified September 21, 2026More metamorphic →

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Physical properties

Formation & geological history

Probably formed by low- to moderate-temperature alteration of ultramafic rock or mafic volcanic rock, then rounded by stream or beach transport. The specimen’s geological age cannot be determined from the photograph.

Uses & applications

Used mainly as a decorative stone, carving material, or collector specimen; similar greenstones may be used locally for aggregate or landscaping. Commercial value is usually low unless unusually patterned, translucent, or from a notable locality.

Geological facts

The image supports a geological specimen, but color and surface texture alone cannot distinguish serpentinite from other greenstones such as altered basalt, nephrite, or chlorite schist.

Field identification & locations

Check streak, hardness, density, magnetism, and acid reaction: serpentinite is commonly soft and waxy, while nephrite is tougher and harder; a fresh fracture is more diagnostic than the polished exterior. Common sources include ultramafic terrains and stream gravels worldwide.