metamorphic

Likely greenstone (metamorphosed basalt)

Metabasalt; commonly composed of chlorite, actinolite, epidote, and albite

AI-generated identification · may be incorrect

Fine-grained, dull to slightly sparkly olive-gray rock with no obvious crystals or cleavage. Typical greenstone minerals have Mohs hardness around 5–6.5; exact properties require testing.

Identified September 28, 2026More metamorphic →

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Physical properties

Fine-grained, dull to slightly sparkly olive-gray rock with no obvious crystals or cleavage. Typical greenstone minerals have Mohs hardness around 5–6.5; exact properties require testing.

Formation & geological history

Forms when basalt is altered by low-grade metamorphism and hydrothermal fluids, often in ancient oceanic crust or volcanic belts. The specimen’s age and precise origin cannot be determined from the image.

Uses & applications

Commonly used as crushed stone or decorative stone; attractive pieces may be cut or polished for crafts and jewelry.

Geological facts

“Greenstone” is a broad field term for green-hued metamorphosed volcanic rock, not a single mineral species.

Field identification & locations

Its fine-grained texture and subdued green-gray color are consistent with greenstone, but the photo alone cannot confirm the identification. Greenstone occurs in metamorphic belts worldwide, including the Canadian Shield and Australia.