metamorphic
Serpentinized ultramafic rock (probable serpentinite)
Serpentinite, dominated by serpentine-group minerals (lizardite/chrysotile/antigorite), with possible magnetite and carbonate
AI-generated identification · may be incorrectDark olive-brown, mottled with cream-white veins or patches; dull to subtly waxy luster and massive texture. Serpentine has Mohs hardness about 2.5–4, poor cleavage, and specific gravity roughly 2.5–2.6; the specimen may include harder carbonate or silica zones.
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Physical properties
Dark olive-brown, mottled with cream-white veins or patches; dull to subtly waxy luster and massive texture. Serpentine has Mohs hardness about 2.5–4, poor cleavage, and specific gravity roughly 2.5–2.6; the specimen may include harder carbonate or silica zones.
Formation & geological history
Forms when mantle-derived peridotite is hydrated and altered by hot, water-rich fluids, commonly along faults and ophiolite belts. The image cannot establish its age; serpentinite exposures occur in many geologic periods.
Uses & applications
Used as decorative stone, carving material, aggregate, and occasionally ornamental slab material. Fibrous chrysotile-rich varieties require caution because asbestos fibers can be hazardous when cut or powdered.
Geological facts
The pale material may be calcite, magnesite, or silica rather than a separate mineral species. Yemen’s western highlands and Red Sea-related ophiolitic fragments make ultramafic-derived rocks regionally plausible, but location alone cannot confirm the identification.
Field identification & locations
Look for a greenish-black waxy surface, very fine massive texture, pale veining, and softness relative to quartz; a streak, hardness, magnetism, acid, and thin-section test would help. Common in serpentinite mélanges and ophiolites.
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