Serpentine

Physical Properties

Hardness: 3-6 (Mohs scale); Color: Shades of green, yellowish, or blackish green; Luster: Waxy, greasy, or silky; Crystal structure: Monoclinic; Cleavage: Good in one direction; Specific gravity: 2.2-2.9

Formation & Geological History

Formed through serpentinization, a metamorphic process where ultramafic rocks (low in silica, high in magnesium/iron) are hydrated at low temperatures. Common in oceanic crust and subduction zones.

Uses & Applications

Used as decorative stone, in jewelry (cabochons), as source for magnesium, and historically as fire-resistant material (asbestos varieties). Polished spheres are popular for meditation and home decor.

Geological Facts

The name comes from 'serpentinus' (Latin for snake-like) due to its mottled green appearance that resembles snake skin. It is the state rock of California.

Field Identification & Locations

Identify in the field by its distinctive 'greasy' feel, green color with mottled veins, and relative softness (can often be scratched by a copper coin or knife). Primarily found in tectonic plate boundaries.

Identified on: 4/14/2026

Mode: Standard