Serpentine (polished serpentinite)

Typically olive to apple-green with mottled or veined patterns, waxy to greasy luster, and commonly polished; Mohs hardness 2.5–4, specific gravity about 2.5–2.6, with poor cleavage and a fine-grained, massive texture. The specimen’s layered green appearance is consistent with polished serpentinite, though image-only identification is approximate.

Forms when ultramafic mantle rocks such as peridotite undergo low-temperature hydration and metamorphism, commonly along tectonic plate boundaries and faults. Serpentinization occurs from the Precambrian to the present.

Used as ornamental stone, beads, carvings, countertops, and decorative tiles; historically used as a jade substitute. Commercial value is generally modest unless unusually patterned or sold as “new jade.”

Serpentinite may contain magnetite and chromite and can be associated with asbestos-forming minerals; do not cut, sand, or powder unknown material without testing. It often has a characteristic slippery, waxy feel.

Common in ophiolites and metamorphic belts, including California, Italy, New Zealand, Canada, and the Appalachians. Field clues include green color, slick/waxy surface, black veining, low hardness, and possible reaction to a steel point.