metamorphic

Serpentinite

Serpentinite, dominated by serpentine-group minerals (lizardite, chrysotile, antigorite)

AI-generated identification · may be incorrect

Typically dark green to mottled green, waxy to greasy luster, massive texture, and Mohs hardness about 2.5–4; specific gravity is roughly 2.5–2.6. The specimen’s green veining and mottled appearance are consistent with serpentinized ultramafic rock, though image-only identification is not definitive.

Identified September 2, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when mantle-derived peridotite or oceanic ultramafic rocks react with water during seafloor alteration or tectonic subduction. Formation ages vary widely, from ancient Precambrian occurrences to modern oceanic systems.

Uses & applications

Used as decorative stone, carvings, countertops, and historically as a source of ornamental “green marble”; fibrous chrysotile-bearing material may present an asbestos hazard and should not be cut or abraded without testing and controls.

Geological facts

Serpentinite commonly contains magnetite, brucite, talc, chromite, and minor carbonate minerals. It is often associated with ophiolites and tectonic plate boundaries.

Field identification & locations

Look for low density, green waxy surfaces, slick or fibrous textures, and possible magnetism from magnetite; it is commonly found in California, Italy, New Zealand, Canada, and ophiolite belts worldwide. A hardness, streak, magnetism, and thin-section test can distinguish it from jade or chlorite-rich rocks.