metamorphic

Serpentinite

Serpentinite (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4

AI-generated identification · may be incorrect

Hardness: 3-6 Mohs. Color: Greenish-gray to dark green with reddish-brown oxidation. Luster: Greasy, waxy, or dull. Structure: Microcrystalline, often fibrous or platy. Cleavage: Poor.

Hardness: 3-6 Mohs
Color: Greenish-gray to dark green with reddish-brown oxidation
Luster: Greasy, waxy, or dull

Identified June 23, 2026More metamorphic →

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Physical properties

Hardness: 3-6 Mohs. Color: Greenish-gray to dark green with reddish-brown oxidation. Luster: Greasy, waxy, or dull. Structure: Microcrystalline, often fibrous or platy. Cleavage: Poor.

Formation & geological history

Formed by the low-temperature hydrothermal alteration (serpentinization) of mafic and ultramafic rocks like peridotite from the Earth's mantle, typically at tectonic plate boundaries.

Uses & applications

Historically used for decorative carvings and architectural stone. Also a source of magnesium and sometimes holds nickel ores. It is often collected for its unique 'snake-skin' appearance.

Geological facts

Serpentinite is the state rock of California. It often contains veins of chrysotile, which is a form of asbestos. The reddish areas in the specimen suggest iron oxidation or the presence of associated hematite/limite.

Field identification & locations

Identified by its waxy feel and characteristic green shades. Often found in ophiolite complexes. To identify in the field, check for a slippery surface when wet and look for associated chromite or magnetite.