metamorphic

Serpentine-rich serpentinite

Serpentinite, chiefly lizardite–chrysotile–antigorite Mg₃Si₂O₅(OH)₄, possibly with calcite and talc

AI-generated identification · may be incorrect

Typically green to yellow-green, mottled, waxy to greasy luster; hardness about 2.5–4, massive rather than visibly crystalline, with poor cleavage. The specimen appears pale green and veined, with whitish-gray matrix and yellowish alteration patches.

Identified September 11, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when ultramafic mantle rocks such as peridotite undergo hydrothermal metamorphism and hydration, commonly along faults and seafloor spreading zones. Individual samples may range from Paleozoic to modern tectonic settings.

Uses & applications

Used as ornamental stone, carving material, countertops, and a source of magnesium and industrial minerals; attractive pieces are collected, though fibrous chrysotile-bearing material should not be cut or powdered.

Geological facts

Serpentinite is California’s state rock and commonly records ancient oceanic mantle exposed in mountain belts. Its green color results from serpentine minerals and associated iron-rich alteration.

Field identification & locations

Identify by its soft, mottled green appearance, waxy feel, and association with dark ultramafic rocks; a steel knife may scratch it. Common in California, the Alps, Appalachians, New Zealand, and ophiolite belts worldwide.