metamorphic

Serpentinite

Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)3Si2O5(OH)4

AI-generated identification · may be incorrect

Hardness: 3-6 Mohs. Color: Various shades of green, often with dark or light streaks. Luster: Greasy, waxy, or silky. Structure: Fibrous or massive monoclinic. Cleavage: Poor; Specific Gravity: 2.5-2.6.

Hardness: 3-6 Mohs
Color: Various shades of green, often with dark or light streaks
Luster: Greasy, waxy, or silky

Identified May 27, 2026More metamorphic →

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Physical properties

Formation & geological history

Formed through the hydration of ultramafic rocks (like peridotite) from the Earth's mantle, typically at tectonic plate boundaries or subduction zones via low-temperature metamorphism (serpentinization).

Uses & applications

Used as an architectural stone for countertops and tiles, a source of magnesium, and occasionally as a gemstone or in carvings. Historically used for asbestos, though modern uses avoid fibrous varieties.

Geological facts

Serpentinite is the state rock of California. It often creates unique, low-fertility soil types that support rare endemic plant species that can tolerate high magnesium and heavy metal levels.

Field identification & locations

Identify by its characteristic waxy 'snake-skin' appearance and green color. Common in ophiolite complexes and metamorphic belts like the Alps, Himalayas, and the Coast Ranges of California.