metamorphic
Serpentine
Antigorite/Chrysotile/Lizardite (Mg,Fe)3Si2O5(OH)4
Hardness: 3-5 on the Mohs scale. Color ranges from light green to dark olive-green, sometimes yellowish or brownish. Luster is greasy, waxy, or silky. Crystal structure is monoclinic, though typically found in massive or compact aggregates with no distinct individual crystals visible to the naked eye.…
- Hardness
- 3-5 on the Mohs scale
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Physical properties
Hardness: 3-5 on the Mohs scale. Color ranges from light green to dark olive-green, sometimes yellowish or brownish. Luster is greasy, waxy, or silky. Crystal structure is monoclinic, though typically found in massive or compact aggregates with no distinct individual crystals visible to the naked eye. Cleavage is poor or absent, and specific gravity is 2.5-2.6.
Formation & geological history
Formed through the process of serpentinization, which is the low-temperature hydrothermal alteration of ultramafic rocks (such as peridotite and dunite) derived from the Earth's mantle, typically occurring in oceanic crust or subduction zone settings.
Uses & applications
Commonly used in ornamental carvings, decorative architecture (as serpentine marble), asbestos manufacturing historically, and popular among rockhounds and lapidary enthusiasts for tumbled stones and cabochons.
Geological facts
Serpentine is the state rock of California. Its unique green coloring and slippery or waxy feel give it its name, which is derived from the Latin word for serpent due to its mottled, snake-skin-like appearance.
Field identification & locations
Can be identified in the field by its characteristic greenish color, soft soapy or waxy feel, and lower hardness compared to quartz (it can easily be scratched with a knife or coin). Commonly found in mountain belts where ancient oceanic crust has been thrust onto land, such as parts of California, Italy, and the Appalachian Mountains.
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