metamorphic

Dark green-black stone, possibly serpentinite

Serpentinite (predominantly serpentine-group minerals; identification from photo is uncertain)

AI-generated identification · may be incorrect

Dark olive to black, wet-looking luster, massive and irregular with no visible crystals. Serpentine minerals are typically Mohs 2.5–5 and have a platy or fibrous structure; hardness and composition cannot be confirmed from the image.

Identified September 28, 2026More metamorphic →

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Physical properties

Formation & geological history

Serpentinite forms when water alters ultramafic rocks, commonly in oceanic crust and mountain-building zones. Such alteration spans geological ages; the specimen’s age and locality are unknown.

Uses & applications

Serpentinite is used as decorative stone, carvings, and occasionally building or ornamental material; this unverified piece has no clear gem-grade features.

Geological facts

Dark, wet surfaces can make many unrelated rocks look similar, including basalt and iron-rich rocks.

Field identification & locations

A field check would examine fresh surfaces, streak, hardness, and reaction to dilute acid; professional testing is needed for a reliable ID. Serpentinite occurs in many mountain belts and ophiolite complexes.