metamorphic
Serpentinite
Serpentinite (Mg, Fe, Ni, Al, Zn, Mn)3Si2O5(OH)4
Hardness: 2.5-4; Color: Greyish-green to dark green; Luster: Greasy, waxy, or silky; Crystal system: Monoclinic; Cleavage: Poor; Specific Gravity: 2.5-2.6
- Hardness
- 2
- Color
- Greyish-green to dark green
- Luster
- Greasy, waxy, or silky
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Physical properties
Hardness: 2.5-4; Color: Greyish-green to dark green; Luster: Greasy, waxy, or silky; Crystal system: Monoclinic; Cleavage: Poor; Specific Gravity: 2.5-2.6
Formation & geological history
Formed through the hydration and metamorphic transformation of ultramafic rocks (like peridotite) from the Earth's mantle at relatively low temperatures and high pressures.
Uses & applications
Used as a source of asbestos in the past, for decorative interior stonework, carvings, and as a railway ballast or road construction material.
Geological facts
It is the official state rock of California; the process of its formation (serpentinization) releases hydrogen and methane which may have supported early life on Earth.
Field identification & locations
Identify by its characteristic waxy 'serpent-like' green color and feel. Often found in ophiolite complexes where oceanic crust has been thrust onto continental crust.
