metamorphic
Serpentinite
Serpentinite; predominantly serpentine-group minerals, commonly with magnetite, talc, and carbonate
AI-generated identification · may be incorrectTypically dark green to black, mottled or veined with pale green/white, with waxy to dull luster; Mohs hardness about 2.5–4, massive texture, and no obvious cleavage. The specimen’s rounded, polished-looking surface and characteristic veining fit serpentinite, though exact identification requires testing.
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Physical properties
Typically dark green to black, mottled or veined with pale green/white, with waxy to dull luster; Mohs hardness about 2.5–4, massive texture, and no obvious cleavage. The specimen’s rounded, polished-looking surface and characteristic veining fit serpentinite, though exact identification requires testing.
Formation & geological history
Forms when ultramafic mantle rocks such as peridotite undergo low-temperature hydrothermal metamorphism and hydration, commonly in oceanic crust and subduction mélanges. Ages range from ancient Precambrian bodies to modern tectonic zones.
Uses & applications
Used as decorative and carving stone, countertops, architectural facing, and historically as a jade substitute; generally modest collector value unless unusually attractive or scientifically documented.
Geological facts
Often mistaken for jade because of its green color and polish. Some varieties contain asbestos-forming minerals, so avoid cutting, drilling, or generating dust without proper testing and protection.
Field identification & locations
Common in ophiolites and tectonic belts, including California, Vermont, Italy, New Zealand, and Canada. Look for a relatively soft, greasy or waxy feel, pale veining, and possible magnetism; acid reaction may indicate associated carbonate.
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