metamorphic
Serpentine (polished/tumbled)
Serpentine-group minerals, chiefly antigorite, Mg₃Si₂O₅(OH)₄
AI-generated identification · may be incorrectTypically olive-green to yellow-green with dark veining, waxy to greasy luster, and mottled patterns; Mohs hardness 2.5–4, generally massive rather than visibly crystalline, with poor cleavage. The rounded, glossy specimen is consistent with polished serpentine, though exact identification requires testing.
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Physical properties
Typically olive-green to yellow-green with dark veining, waxy to greasy luster, and mottled patterns; Mohs hardness 2.5–4, generally massive rather than visibly crystalline, with poor cleavage. The rounded, glossy specimen is consistent with polished serpentine, though exact identification requires testing.
Formation & geological history
Forms when ultramafic rocks such as peridotite undergo low-temperature hydration and alteration; many deposits formed during the Paleozoic–Mesozoic and younger tectonic events. Common sources include California, Vermont, New Zealand, Italy, Canada, and Afghanistan.
Uses & applications
Used as an ornamental stone, carvings, beads, cabochons, and decorative tile; historically used for architectural facing. Avoid prolonged dust exposure because some serpentinite deposits can contain asbestos-forming minerals.
Geological facts
Serpentine is California’s state rock and gives its name to serpentinite, a rock composed largely of serpentine minerals. Its green color and dark mesh-like veining can resemble jade, but it is much softer.
Field identification & locations
Identify by its low hardness, waxy feel, green mottling, and ability to scratch with a steel knife; it should not scratch glass. The image could also represent a related greenstone or nephrite, so laboratory analysis is needed for certainty.
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