Serpentinite

Physical Properties

Hardness: 3-6 Mohs. Color: Greenish-gray, dark green, or black with mottled patterns. Luster: Greasy, waxy, or silky. Structure: Non-foliated to massive. Specific Gravity: 2.5-2.6.

Formation & Geological History

Formed through the hydration and metamorphic transformation of ultramafic rocks (like peridotite) from the Earth's mantle, typically at tectonic plate boundaries/subduction zones.

Uses & Applications

Used as an ornamental stone in architecture, a source of magnesium, and historically as a source of asbestos. High-quality varieties like bowenite are used in jewelry.

Geological Facts

It is the official state rock of California. The name comes from its resemblance to the skin of a serpent. Serpentine minerals can sequester carbon dioxide from the atmosphere.

Field Identification & Locations

Identified by its waxy feel, green mottled color, and relative softness. Commonly found in ophiolites and mountain ranges like the Alps, Himalayas, and the Coast Ranges of California.

Identified on: 5/1/2026

Mode: Standard