metamorphic
Polished serpentine-rich stone (likely serpentinite)
Serpentinite; chiefly serpentine-group minerals, Mg₃Si₂O₅(OH)₄, with dark magnetite/mesh veins
AI-generated identification · may be incorrectDark gray-green, waxy to subvitreous luster, rounded and polished; typically Mohs 2.5–4, with poor cleavage and a fine-grained or interlocking texture. The abundant black veining may represent magnetite, chromite, or altered fractures; exact identification requires testing.
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Physical properties
Dark gray-green, waxy to subvitreous luster, rounded and polished; typically Mohs 2.5–4, with poor cleavage and a fine-grained or interlocking texture. The abundant black veining may represent magnetite, chromite, or altered fractures; exact identification requires testing.
Formation & geological history
Forms when ultramafic mantle rocks such as peridotite are hydrated during metamorphism, commonly along oceanic crust and tectonic plate boundaries. Serpentinization is mainly Paleozoic to recent, depending on the locality.
Uses & applications
Carved ornaments, cabochons, decorative stone, and small polished specimens; some varieties are used architecturally, though fibrous asbestos-bearing material should not be cut or powdered.
Geological facts
The characteristic network or “mesh” texture reflects replacement of original olivine and pyroxene by serpentine. It may resemble jade, but is generally softer and less translucent.
Field identification & locations
Look for green-gray color, waxy feel, low hardness, and dark vein networks; a steel blade may scratch it, while quartz will not. Common sources include California, Italy, New Zealand, Canada, and serpentinite belts worldwide.
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