Serpentine

Physical Properties

Hardness: 3-6 (Mohs); Color: Olive green to yellowish-green with dark mottled patches; Luster: Waxy to greasy; Crystal Structure: Monoclinic; Cleavage: Poor; Specific Gravity: 2.5-2.6

Formation & Geological History

Formed by the hydrothermal alteration of ultramafic rock (serpentinization of olivine and pyroxene) at low temperatures in the presence of water. Found commonly along tectonic plate boundaries and ophiolites.

Uses & Applications

Used as an ornamental stone for sculpture and architectural facades. Historically used to make jewelry and as a source of magnesium; fibrous varieties were once used for asbestos.

Geological Facts

Serpentine is the official state rock of California. Its name is derived from its snake-like appearance, specifically its green color and scaly texture.

Field Identification & Locations

Identify by its greasy feel and green mottled color. Often found in mountainous regions where oceanic crust has been pushed onto continental crust. Take care as some varieties may contain fibrous asbestos minerals.

Identified on: 5/1/2026

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