metamorphic
Serpentinite
Serpentinite (complex silicate minerals including Mg3Si2O5(OH)4)
Hardness: 3–6 (variable), Color: Dark green to light green, black, or mottled, Luster: Waxy to greasy, Crystal structure: Monoclinic, Cleavage: Poorly developed, Specific gravity: 2.2–2.9
Identified More metamorphic →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 3–6 (variable), Color: Dark green to light green, black, or mottled, Luster: Waxy to greasy, Crystal structure: Monoclinic, Cleavage: Poorly developed, Specific gravity: 2.2–2.9
Formation & geological history
Formed through the hydration of ultramafic rocks (like peridotite) from the Earth’s mantle at high pressure and relatively low temperatures, a process called serpentinization. Often associated with subduction zones.
Uses & applications
Used as decorative architectural stone, in sculptures, as a source of magnesium, and historically as a source of asbestos. High-quality varieties like 'Bowenite' are used in jewelry as jade substitutes.
Geological facts
It is the official state rock of California. The name comes from its green, scaly appearance which resembles the skin of a serpent.
Field identification & locations
Identify in the field by its dark green, mottled color, waxy feel, and slippery surfaces (slickensides). Commonly found in ophiolite complexes and tectonic plate boundaries such as the Alps, Himalayas, and the Coast Ranges of North America.
More like this
