metamorphic
Serpentinite
Serpentinite (composed primarily of Serpentine-group minerals: (Mg,Fe,Ni,Al,Zn,Mn)2-3(Si,Al,Fe)2O5(OH)4)
Hardness: 3-6 (variable); Color: Green, bluish-gray, or black; Luster: Greasy, waxy, or silky; Crystal Structure: Monoclinic; Cleavage: Good in one direction depending on mineral species; Specific Gravity: 2.5-2.6
- Hardness
- 3-6 (variable)
- Color
- Green, bluish-gray, or black
- Luster
- Greasy, waxy, or silky
Identified More metamorphic →
Explore Serpentinite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness: 3-6 (variable); Color: Green, bluish-gray, or black; Luster: Greasy, waxy, or silky; Crystal Structure: Monoclinic; Cleavage: Good in one direction depending on mineral species; Specific Gravity: 2.5-2.6
Formation & geological history
Formed through serpentinization, an exothermic reaction where ultramafic rocks (like peridotite) from the Earth's mantle are hydrated and oxidized at low temperatures during tectonic uplift and subduction.
Uses & applications
Decorative stone, source of magnesium, historical source of asbestos (in fibrous forms), used for carvings and sometimes as a building stone.
Geological facts
Serpentinite is the official state rock of California. It often creates unique soil conditions (serpentine soils) that are low in nutrients but high in heavy metals, leading to specialized endemic plant species.
Field identification & locations
Identify by its characteristic 'snake-skin' appearance, greasy feel when wet, and common occurrence in ophiolite complexes. Often found in riverbeds near tectonic boundaries or mountain ranges like the Alps or the California Coast Ranges.
More like this
