metamorphic

Serpentinite

Serpentinite, a rock composed mainly of serpentine-group minerals (approximately Mg₃Si₂O₅(OH)₄)

AI-generated identification · may be incorrect

Dark green to black, mottled and locally glossy, with a waxy-to-greasy luster; hardness commonly 2.5–5.5, variable crystal texture, and generally no obvious cleavage. The image alone cannot confirm the identification or provide reliable physical measurements.

Identified September 29, 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

Formation & geological history

Forms when water alters ultramafic rocks such as peridotite, commonly along oceanic crust and convergent plate boundaries; alteration can occur across a wide range of geological ages.

Uses & applications

Used as decorative and carving stone, and historically as a source of asbestos-bearing minerals; some varieties are polished for ornaments. Fibrous varieties require caution because inhaled asbestos fibers are hazardous.

Geological facts

Serpentinite is a rock, not a single mineral, and its color and texture vary with mineral mix and alteration.

Field identification & locations

A likely field clue is a green-to-black, mottled, relatively soft rock with a smooth or waxy surface; confirm with mineralogical testing, since appearance is not diagnostic. Occurs in serpentinite belts worldwide.