metamorphic
Serpentine-rich metamorphic rock
Serpentinite; chiefly antigorite/lizardite/chrysotile, commonly with magnetite and carbonate
AI-generated identification · may be incorrectTypically pale to dark green, yellow-green, or mottled, with a waxy to greasy luster and fibrous, scaly, or massive texture; Mohs hardness is about 2.5–4, with no consistent cleavage. The specimen appears weathered and foliated, but exact identification would require testing.
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Physical properties
Typically pale to dark green, yellow-green, or mottled, with a waxy to greasy luster and fibrous, scaly, or massive texture; Mohs hardness is about 2.5–4, with no consistent cleavage. The specimen appears weathered and foliated, but exact identification would require testing.
Formation & geological history
Forms when ultramafic mantle rocks such as peridotite are hydrated during hydrothermal alteration, commonly along plate boundaries and ophiolites. Serpentinization can occur from Precambrian to modern geological ages.
Uses & applications
Used as decorative and architectural stone, carving material, and historically for asbestos-bearing products; chrysotile-bearing material should not be cut, drilled, or powdered. Common pieces have modest collector value.
Geological facts
Green color results from serpentine minerals, while dark veins may contain magnetite or other alteration minerals. Some serpentinite fluoresces weakly and may feel unusually smooth or waxy.
Field identification & locations
Common in California, Italy, New Zealand, Canada, and ophiolite belts worldwide; identify by green mottling, low hardness, waxy feel, and possible magnetic response. Estimated value: $5–$30 for a small common specimen, higher if polished or exceptionally patterned.
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