Serpentine (Serpentinite)

Physical Properties

Hardness: 3-6 (Mohs scale), Color: Dark green to waxy grey-green with mottled veins, Luster: Greasy/Waxy to silky, Crystal structure: Monoclinic (microcrystalline), Cleavage: Poorly defined, Specific gravity: 2.5-3.2

Formation & Geological History

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

Uses & Applications

Used as an ornamental stone in architecture, as a source of magnesium, and in jewelry (often as a jade simulant); historically used for heat-resistant materials.

Geological Facts

Serpentinite is the official State Rock of California. Large deposits are often associated with ophiolites, which are sections of the Earth's oceanic crust and upper mantle uplifted onto land.

Field Identification & Locations

Identify by its characteristic 'snake-skin' green color and waxy feel. It is commonly found in coastal mountain ranges and areas with ancient subduction zones. Collectors should look for the unique mottled texture and variations in green intensity.

Identified on: 4/13/2026

Mode: Standard