metamorphic

Tumbled serpentine

Serpentine-group minerals, chiefly antigorite and/or lizardite; commonly Mg₃Si₂O₅(OH)₄

AI-generated identification · may be incorrect

Olive-green to yellow-green, mottled and waxy, with a polished surface and typically no visible crystal faces; Mohs hardness 2.5–4, opaque to translucent, low vitreous-to-waxy luster, massive rather than strongly cleaved. The photograph is consistent with serpentine, though exact identification would require testing.

Identified September 8, 2026More metamorphic →

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Physical properties

Formation & geological history

Forms when ultramafic mantle rocks such as peridotite undergo low-temperature hydration and alteration (serpentinization), commonly in oceanic crust and tectonic boundaries; specimens may be geologically Paleozoic to modern. Often occurs with magnetite, talc, and chromite.

Uses & applications

Used as a decorative stone, carving material, ornamental aggregate, and historically as a minor source of asbestos-bearing minerals; tumbled pieces are sold as inexpensive lapidary specimens.

Geological facts

Its green color results from iron and nickel substitutions in hydrated magnesium silicates. Some serpentine rocks contain chrysotile asbestos, so avoid cutting or generating dust unless confirmed asbestos-free.

Field identification & locations

Identify by olive mottling, waxy polish, relatively low hardness, and a pale streak; it is common in California, Italy, New Zealand, Canada, and ultramafic terranes worldwide. A knife may scratch it, unlike quartz.