metamorphic

Dark green-black stone, likely serpentinite

Serpentinite; chiefly antigorite/lizardite/chrysotile group minerals, commonly with magnetite

AI-generated identification · may be incorrect

Typically Mohs 2.5–4, dark green to black, waxy to greasy luster, fine-grained and massive; may show mottling, slickensides, and minor magnetism. The specimen appears rough and irregular, but image-only identification is not definitive.

Identified September 19, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when ultramafic mantle rocks such as peridotite hydrate during metamorphism, commonly along tectonic plate boundaries and faults. Serpentinization occurs from the Precambrian to the present.

Uses & applications

Used as decorative and carving stone, countertops, aggregates, and historically as a source of asbestos-bearing material; attractive pieces are collected but are generally not jewelry-grade.

Geological facts

Serpentinite can resemble jade, but is usually softer and less tough. Avoid cutting, sanding, or powdering unknown specimens because some varieties contain fibrous chrysotile asbestos.

Field identification & locations

Common in ophiolites and tectonic belts, including California, Italy, New Zealand, and the Alps. Field clues include green-black color, waxy feel, low hardness, and possible magnetism; jade testing requires hardness, density, and laboratory analysis.