metamorphic

Likely serpentinite

Serpentinite, composed mainly of serpentine-group minerals (e.g., lizardite, antigorite, or chrysotile)

AI-generated identification · may be incorrect

Greenish-gray, dull to slightly waxy and massive; serpentine minerals have Mohs hardness about 2.5–4 and a monoclinic or, for some varieties, trigonal structure. The photo alone does not show diagnostic features clearly enough for a confident identification.

Identified October 6, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when water alters ultramafic rocks such as peridotite, commonly during seafloor alteration or metamorphism along tectonic plate boundaries; formation age depends on its source rock.

Uses & applications

Serpentinite is used as decorative stone, carving material, and occasionally as a source of industrial minerals; this small rough piece is mainly a collector specimen.

Geological facts

Serpentinite often has mottled green color and may contain veins of magnetite or other minerals; some varieties contain asbestos-forming chrysotile.

Field identification & locations

The specimen appears to be a rough, green-gray rock, but color alone is insufficient to distinguish serpentinite from several other common rocks. Check for a waxy feel, relatively low hardness, and a pale streak; avoid grinding or cutting unknown material because it could contain fibrous minerals.