metamorphic

Polished serpentine (likely)

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

AI-generated identification · may be incorrect

Dark green-black, waxy to vitreous polished luster with mottled pale veining and possible magnetite or chromite specks. Serpentine has Mohs hardness about 2.5–4, no prominent cleavage, and specific gravity around 2.5–2.6; the spherical shape is human-polished.

Identified September 3, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when ultramafic mantle rocks such as peridotite hydrate during hydrothermal alteration, commonly along oceanic crust and plate boundaries. Serpentinization ranges from ancient Precambrian to modern geological settings; age cannot be determined from the image.

Uses & applications

Used for ornamental carvings, spheres, countertops, decorative stone, and occasionally low-cost jewelry. Avoid prolonged skin contact with dusty material because some serpentinites may contain fibrous chrysotile asbestos.

Geological facts

Its dark green-black appearance can resemble jade, basalt, or obsidian, but its waxy surface and mottled veining are characteristic clues. A polished sphere does not preserve enough texture for certain identification.

Field identification & locations

Common sources include Italy, New Zealand, California, Canada, Russia, and Afghanistan. Confirm with hardness, streak, density, and laboratory testing; visual identification alone is provisional.