metamorphic
Serpentine (Serpentinite)
Antigorite, Lizardite, or Chrysotile (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4
Hardness: 3-6 (variable); Color: typically dark green, olive, or yellowish-green; Luster: waxy, greasy, or silky; Crystal Structure: Monoclinic; Cleavage: poor/conchoidal; Specific Gravity: 2.5-2.6
- Hardness
- 3-6 (variable)
- Color
- typically dark green, olive, or yellowish-green
- Luster
- waxy, greasy, or silky
Identified More metamorphic →
Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 3-6 (variable); Color: typically dark green, olive, or yellowish-green; Luster: waxy, greasy, or silky; Crystal Structure: Monoclinic; Cleavage: poor/conchoidal; Specific Gravity: 2.5-2.6
Formation & geological history
Formed through the hydration of ultramafic rocks (like peridotite) from the Earth’s mantle, a process known as serpentinization. This usually occurs at tectonic plate boundaries where seawater interacts with mantle rocks under heat and pressure.
Uses & applications
Used as decorative stone in interior architecture, ornamental carvings, and historically as a source of asbestos (specifically the chrysotile variety). It is also a gemstone used in jewelry.
Geological facts
Serpentinite is the official state rock of California. It often creates 'serpentine barrens'—soils rich in magnesium and heavy metals but poor in calcium, leading to unique, specialized ecosystems.
Field identification & locations
Identify in the field by its dark green color, waxy to soapy feel, and smooth surfaces. It is commonly found in ophiolitic belts, such as the Coast Ranges of California, the Alps, and the Appalachian Mountains.
More like this
