metamorphic
Greenstone (likely altered basalt or serpentinite)
Chlorite-rich metabasalt or serpentinite; exact identification requires testing
AI-generated identification · may be incorrectDark green, fine-grained, dull to slightly waxy luster, massive texture, and irregular fractures. Likely Mohs hardness 3–6 depending on composition; no visible cleavage or crystals.
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Physical properties
Dark green, fine-grained, dull to slightly waxy luster, massive texture, and irregular fractures. Likely Mohs hardness 3–6 depending on composition; no visible cleavage or crystals.
Formation & geological history
Probably a weathered mafic volcanic rock altered by low-grade metamorphism or hydrothermal fluids; such rocks commonly formed in ancient oceanic crust, often Paleozoic or older.
Uses & applications
Used locally as crushed aggregate, landscaping stone, or carving material; attractive pieces may be collected, but this specimen has little commercial gemstone value.
Geological facts
“Greenstone” is a field term rather than one mineral species and may include chlorite schist, epidote-rich basalt, or serpentinite.
Field identification & locations
Green color and fine-grained massive texture support altered basalt or serpentinite. Check streak, hardness, density, magnetic response, and whether a fresh surface shows black pyroxene or fibrous/waxy serpentine; common in ophiolites and metamorphic belts.
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