metamorphic
Tumbled greenstone (likely serpentine-rich)
Greenstone; commonly metamorphosed mafic rock composed of actinolite/chlorite with epidote and albite
AI-generated identification · may be incorrectOpaque olive-green, mottled, smooth and rounded; likely Mohs 3–6 depending on minerals, with a dull to slight waxy luster. Fine-grained, so individual crystals and cleavage are not visible; the photo alone cannot confirm its exact identity.
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Physical properties
Opaque olive-green, mottled, smooth and rounded; likely Mohs 3–6 depending on minerals, with a dull to slight waxy luster. Fine-grained, so individual crystals and cleavage are not visible; the photo alone cannot confirm its exact identity.
Formation & geological history
Forms when basalt or other mafic rock is altered by low-grade metamorphism and hydrothermal fluids. Such rocks occur in ancient oceanic crust and volcanic belts; the specimen’s age and locality are unknown.
Uses & applications
Tumbled greenstone is mainly used for decorative stones, craftwork, and mineral collecting; related greenstones are also used as local building stone.
Geological facts
“Greenstone” is a descriptive field term, not one single mineral species, and can refer to several green, altered mafic rocks.
Field identification & locations
The rounded shape and polish indicate a processed geological specimen. Check hardness, streak, and mineral texture to distinguish it from serpentine, jade, or other green stones; greenstone occurs in metamorphic belts worldwide.
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