metamorphic
Chromite-bearing serpentinite (probable)
Serpentinite with disseminated chromite; chromite is FeCr₂O₄
AI-generated identification · may be incorrectDark green to black, with glossy to submetallic patches and a rough, granular surface. Serpentine has Mohs hardness about 2.5–5.5; chromite is about 5.5; the image alone does not show diagnostic crystal structure or cleavage clearly.
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Physical properties
Dark green to black, with glossy to submetallic patches and a rough, granular surface. Serpentine has Mohs hardness about 2.5–5.5; chromite is about 5.5; the image alone does not show diagnostic crystal structure or cleavage clearly.
Formation & geological history
Serpentinite forms when water alters ultramafic mantle rocks, commonly during seafloor alteration or metamorphism; chromite may persist from the original rock. Age depends on its source and cannot be determined from the image.
Uses & applications
Chromite is the principal chromium ore, used in stainless steel, alloys, and refractory materials; serpentinite is sometimes used as decorative stone or collected.
Geological facts
The specimen’s dark, shiny appearance is consistent with chromite-bearing ultramafic rock, but visual identification is uncertain without tests or a fresh surface.
Field identification & locations
Look for greenish serpentinite matrix with dense, dark, relatively heavy chromite grains; common in ultramafic belts and ophiolites. Confirm with hardness, streak, and density tests.
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