metamorphic
Serpentinized ultramafic rock (likely serpentinite)
Serpentinite; chiefly serpentine-group minerals (chrysotile, lizardite, antigorite), with olivine/pyroxene relics and possible magnetite
AI-generated identification · may be incorrectGreen, cream, gray, and rusty-brown mottling with a waxy to dull luster and massive, granular texture; typically Mohs 2.5–4, with no consistent cleavage and specific gravity about 2.5–2.7. The pale angular patches may be altered mineral remnants or carbonate veins.
Identified More metamorphic →
Explore Serpentinized ultramafic rock (likely serpentinite) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Green, cream, gray, and rusty-brown mottling with a waxy to dull luster and massive, granular texture; typically Mohs 2.5–4, with no consistent cleavage and specific gravity about 2.5–2.7. The pale angular patches may be altered mineral remnants or carbonate veins.
Formation & geological history
Forms when mantle-derived peridotite is hydrated and metamorphosed by low-temperature hydrothermal fluids, commonly along faults and ophiolite belts; ages range from Precambrian to modern tectonic settings.
Uses & applications
Used as decorative stone, carving material, aggregate, and historically as a source of asbestos where chrysotile is present; attractive polished pieces may be collected, but fibrous material should not be cut or handled dusty.
Geological facts
Serpentinite commonly contains magnetite and can be weakly magnetic. Its green coloration results from serpentinization rather than primary green crystals.
Field identification & locations
Identify by mottled green color, waxy feel, low hardness, vein networks, and possible magnetism; common in California, Italy, New Zealand, Canada, and oceanic ophiolites. Confirm with thin section, XRD, or Raman analysis.
More like this
