metamorphic
Polished serpentine breccia
Serpentinite, commonly serpentine-group minerals with carbonate and magnetite
AI-generated identification · may be incorrectTypically dark green to black with irregular pale veins and brecciated patches; waxy to greasy luster, Mohs hardness about 2.5–4, poor cleavage, and massive/interlocking crystal texture. The image appears to show a polished slab or tile.
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Physical properties
Typically dark green to black with irregular pale veins and brecciated patches; waxy to greasy luster, Mohs hardness about 2.5–4, poor cleavage, and massive/interlocking crystal texture. The image appears to show a polished slab or tile.
Formation & geological history
Forms when ultramafic mantle rocks, especially peridotite, undergo hydrothermal alteration and hydration during metamorphism; common in ancient and active subduction zones, with ages varying by tectonic setting.
Uses & applications
Used as decorative stone, carvings, countertops, and collector specimens; historically used for ornamental architecture. Avoid cutting or grinding without dust controls because some serpentinite can contain fibrous chrysotile asbestos.
Geological facts
Serpentine is a mineral group rather than one single mineral, including antigorite, lizardite, and chrysotile. Magnetite commonly gives serpentinite its dark color and can cause weak magnetic attraction.
Field identification & locations
Identify by its green-black mottled appearance, polished waxy surface, soft relative hardness, and occasional magnetism; it is widespread in California, Italy, New Zealand, Canada, and the Himalaya.
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