metamorphic
Greenstone (altered volcanic rock)
Chlorite–epidote–actinolite-bearing metabasalt (tentative identification)
AI-generated identification · may be incorrectDull, mottled olive-green, fine-grained matrix with pinkish mineral patches and a rough, irregular surface. Hardness and exact mineralogy cannot be determined reliably from the photograph; greenstone commonly contains chlorite, epidote, actinolite, and plagioclase.
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Physical properties
Dull, mottled olive-green, fine-grained matrix with pinkish mineral patches and a rough, irregular surface. Hardness and exact mineralogy cannot be determined reliably from the photograph; greenstone commonly contains chlorite, epidote, actinolite, and plagioclase.
Formation & geological history
Typically forms when basalt is altered by low-grade metamorphism and hydrothermal fluids, often in ancient oceanic crust or volcanic belts; its age depends on its source locality.
Uses & applications
Greenstone is used as crushed stone and, when attractive and durable, as an ornamental or carving material.
Geological facts
The name “greenstone” describes color and alteration rather than one uniquely defined rock composition.
Field identification & locations
Its green color and possible light pink inclusions fit altered volcanic rock, but the image alone cannot confirm the identification or inclusions. Common in metamorphosed volcanic terranes; a fresh surface and mineral tests would help distinguish it from other green rocks.
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