metamorphic

Serpentinite

Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)2-3(Si, Al, Fe)2O5(OH)4

AI-generated identification · may be incorrect

Hardness: 3-6 Mohs; Color: Dark green to black, mottled; Luster: Waxy, greasy, or silky; Crystal Structure: Monoclinic; Cleavage: Poor; Specific Gravity: 2.5-3.2

Hardness: 3-6 Mohs
Color: Dark green to black, mottled
Luster: Waxy, greasy, or silky

Identified July 19, 2026More metamorphic →

Explore Serpentinite in the encyclopedia →

Identify your own rocks.

Get a report just like this from any photo, free.

App Store Google Play

Physical properties

Hardness: 3-6 Mohs; Color: Dark green to black, mottled; Luster: Waxy, greasy, or silky; Crystal Structure: Monoclinic; Cleavage: Poor; Specific Gravity: 2.5-3.2

Formation & geological history

Formed through the hydrothermal alteration of ultramafic rocks (like peridotite) from the Earth’s mantle at low temperatures, typically at tectonic plate boundaries/subduction zones.

Uses & applications

Used as decorative stone, construction material, a source of magnesium, and historically as a source of asbestos (though not all contain it). It is also a popular collector specimen.

Geological facts

Serpentinite is the official state rock of California. It is often called 'snake rock' because its texture and color resemble snakeskin. It forms in hydrated oceanic crust.

Field identification & locations

Identify by its characteristic waxy feel, green mottled appearance, and relatively soft surface. Commonly found in ophiolite complexes and along fault zones.