metamorphic
Likely greenstone (chlorite-rich metamorphic rock)
Greenstone, commonly altered basalt containing chlorite, epidote, and actinolite
AI-generated identification · may be incorrectSmall, dark olive-green, rough fragment with a dull to slightly sparkly surface. Exact hardness, mineral composition, and crystal structure cannot be confirmed from the photograph; greenstone is typically fine-grained and around 5–6 on the Mohs scale.
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Physical properties
Small, dark olive-green, rough fragment with a dull to slightly sparkly surface. Exact hardness, mineral composition, and crystal structure cannot be confirmed from the photograph; greenstone is typically fine-grained and around 5–6 on the Mohs scale.
Formation & geological history
Typically forms when basalt or related volcanic rock is metamorphosed and altered by hot, water-rich fluids; age depends on its source rock and locality.
Uses & applications
Greenstone is used as crushed aggregate and, when attractive or workable, for carvings and ornamental objects.
Geological facts
The name describes a green appearance rather than one unique mineral or fixed composition.
Field identification & locations
Greenstone commonly occurs in metamorphosed volcanic belts; field identification relies on its green color and fine-grained texture, with mineral tests or laboratory analysis needed for confirmation.
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