Serpentine

Physical Properties

Hardness: 3–6 on Mohs scale; Color: olive green to yellowish-green with dark mottling; Luster: greasy, waxy, or silky; Crystal structure: Monoclinic; Cleavage: poor/basal; Specific gravity: 2.5–2.8

Formation & Geological History

Formed through 'serpentinization,' a low-temperature metamorphic process where ultramafic rocks from the Earth's mantle are hydrated by hydrothermal fluids at tectonic plate boundaries. Common in ophiolite complexes.

Uses & Applications

Used primarily in jewelry (beads, cabochons), ornamental carvings, architectural stone (Vermont 'Marble'), and historically as a source of asbestos. High-quality translucent varieties are used as jade substitutes.

Geological Facts

Serpentine is the official state rock of California. Its name is derived from the Latin 'serpentinus,' meaning 'resembling a serpent,' due to its mottled green appearance that mimics snakeskin.

Field Identification & Locations

Identify by its characteristic greasy luster and mottled green color. It is often found in mountainous regions where seafloor crust has been pushed onto land. It is softer than jade and can be scratched by a steel knife.

Identified on: 4/23/2026

Mode: Standard