Rock Identifier
Tumbled serpentine (likely) (Serpentine-group minerals, commonly lizardite or antigorite; approximate composition Mg₃Si₂O₅(OH)₄) — mineral
mineral

Tumbled serpentine (likely)

Serpentine-group minerals, commonly lizardite or antigorite; approximate composition Mg₃Si₂O₅(OH)₄

AI-generated identification · may be incorrect

Small polished/tumbled stone with yellow-green mottling and a waxy to dull luster; serpentine has Mohs hardness 2.5–4, nonmetallic luster, and typically massive rather than visibly crystalline structure. Exact identification from the photo is uncertain; similar stones include jade, prehnite, or chrysoprase.

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Physical properties

Small polished/tumbled stone with yellow-green mottling and a waxy to dull luster; serpentine has Mohs hardness 2.5–4, nonmetallic luster, and typically massive rather than visibly crystalline structure. Exact identification from the photo is uncertain; similar stones include jade, prehnite, or chrysoprase.

Formation & geological history

Forms when magnesium-rich ultramafic rocks such as peridotite hydrate during hydrothermal or tectonic alteration, commonly in ancient oceanic crust and mountain belts. Serpentinization occurs from the Precambrian to the present.

Uses & applications

Used as ornamental stone, carvings, beads, countertops, and decorative tumbled specimens; some varieties are marketed as “new jade.” Value is generally modest unless color, translucency, and carving quality are exceptional.

Geological facts

Its green color comes from iron and nickel-bearing serpentine minerals. A similar-looking material may be nephrite jade, which is substantially harder and tougher.

Field identification & locations

Common localities include California, Italy, New Zealand, Canada, and the Ural Mountains. Field clues are greasy/waxy feel, low hardness, green-yellow veining, and possible scratching by a steel knife; acid and hardness tests help distinguish it from jade.