metamorphic
Tumbled serpentine or serpentinite
Serpentine-group minerals, chiefly antigorite, lizardite, or chrysotile; approximate formula Mg₃Si₂O₅(OH)₄
AI-generated identification · may be incorrectLight olive-gray, waxy to dull luster with pale veining and polished/tumbled surfaces; hardness about 2.5–4 Mohs, typically massive rather than visibly crystalline, with uneven fracture and specific gravity around 2.5–2.6.
Identified More metamorphic →
Explore Tumbled serpentine or serpentinite in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Light olive-gray, waxy to dull luster with pale veining and polished/tumbled surfaces; hardness about 2.5–4 Mohs, typically massive rather than visibly crystalline, with uneven fracture and specific gravity around 2.5–2.6.
Formation & geological history
Forms when ultramafic mantle rocks such as peridotite hydrate during hydrothermal alteration, commonly in ancient and active plate-boundary zones; the pictured piece is human-tumbled. Exact age cannot be determined visually.
Uses & applications
Used as ornamental stone, carvings, cabochons, countertops, and low-cost lapidary material; fibrous chrysotile varieties are hazardous if they release asbestos fibers and should not be cut or abraded.
Geological facts
Its green color comes from iron and nickel-bearing serpentine minerals, while pale mesh-like lines may reflect veining or the original rock texture. Serpentinite is California’s state rock.
Field identification & locations
Identify by its green-gray color, very low hardness, waxy feel, and commonly mottled or veined texture; common sources include California, Italy, New Zealand, Canada, and Zimbabwe. A scratch test and specific mineral analysis are needed for certainty.
More like this
