metamorphic
Likely serpentinite or serpentine-rich rock
Serpentinite, composed chiefly of serpentine-group minerals (e.g., antigorite, lizardite, or chrysotile)
AI-generated identification · may be incorrectThe small specimen appears pale green-gray, smooth, and rounded, with a subdued waxy-to-dull luster; the image is not detailed enough to confirm texture or cleavage. Serpentine minerals are typically Mohs 2.5–5.5, with variable crystal structure and specific gravity around 2.5–2.6.
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Physical properties
The small specimen appears pale green-gray, smooth, and rounded, with a subdued waxy-to-dull luster; the image is not detailed enough to confirm texture or cleavage. Serpentine minerals are typically Mohs 2.5–5.5, with variable crystal structure and specific gravity around 2.5–2.6.
Formation & geological history
Serpentinite forms when water alters ultramafic rocks, commonly in oceanic crust and mantle, during hydrothermal or metamorphic processes. Its age depends on the source rock and alteration event.
Uses & applications
Used decoratively and as carving stone; some serpentinite is sold as ornamental stone. Avoid cutting or grinding unidentified material because some serpentine rocks can contain asbestos-form chrysotile.
Geological facts
Serpentinite is named for its often mottled, snake-skin-like appearance, though this smooth pebble does not show that pattern clearly.
Field identification & locations
The location near 35.4°N, 118.9°W is broadly compatible with serpentinite in California’s complex fault and ophiolite terrains, but the photo alone cannot establish the identification. Check for a waxy feel and green mottling; a streak, hardness test, or close-up would help distinguish it from other pale pebbles.
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