metamorphic
Polished dark green stone (likely serpentine or greenstone)
Serpentine-group mineral aggregate, commonly antigorite/lizardite; identification is uncertain from the image
AI-generated identification · may be incorrectDark olive-green to black, smooth polished surface, likely waxy to subvitreous luster, with no visible crystals or cleavage. Serpentine has Mohs hardness 2.5–4 and specific gravity about 2.5–2.6; the rounded form appears tumbled or polished.
Identified More metamorphic →
Explore Polished dark green stone (likely serpentine or greenstone) in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Dark olive-green to black, smooth polished surface, likely waxy to subvitreous luster, with no visible crystals or cleavage. Serpentine has Mohs hardness 2.5–4 and specific gravity about 2.5–2.6; the rounded form appears tumbled or polished.
Formation & geological history
Serpentine forms when ultramafic mantle rocks such as peridotite undergo hydration and alteration, commonly in oceanic tectonic zones; many deposits are Paleozoic to Mesozoic or younger.
Uses & applications
Used for ornamental stone, carvings, beads, cabochons, and occasionally architectural surfaces. Small common polished pieces generally have modest value.
Geological facts
Serpentine’s color ranges from pale yellow-green to nearly black, often with mottling or veining. Similar-looking materials include nephrite jade, chlorite-rich rock, basalt, and polished glass.
Field identification & locations
Field clues include unusually low hardness, greasy or waxy feel, green streaking or mottling, and possible fibrous texture; a hardness test and specific-gravity or mineralogical analysis are needed for confirmation. Common localities include California, Italy, New Zealand, Canada, and the Ural Mountains.
More like this
