metamorphic
Greenstone pebble
Likely chlorite- or epidote-bearing metamafic rock (metabasalt/greenschist)
AI-generated identification · may be incorrectFine-grained, rounded and water-worn, olive-green with darker mottling and weak earthy-to-waxy luster. Likely hardness about 5–7 Mohs, very low porosity, and no obvious cleavage; exact mineralogy requires testing.
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Physical properties
Fine-grained, rounded and water-worn, olive-green with darker mottling and weak earthy-to-waxy luster. Likely hardness about 5–7 Mohs, very low porosity, and no obvious cleavage; exact mineralogy requires testing.
Formation & geological history
Probably altered basalt metamorphosed under greenschist-facies conditions, then eroded and rounded in a stream or beach environment. The original basalt may be Paleozoic or younger, but age cannot be determined from the image.
Uses & applications
Used mainly as a decorative pebble, landscaping stone, or lapidary material; attractive pieces may be polished for cabochons or carvings. It has little industrial value at this small size.
Geological facts
Green coloration commonly comes from chlorite, epidote, actinolite, or serpentine rather than a single mineral. “Greenstone” is a broad field term and should not be confused with jade without laboratory testing.
Field identification & locations
Identify by its dense fine grain, green-black mottling, and lack of visible crystals; a streak, hardness, magnetism, and acid test can help distinguish it from jade or serpentinite. Common in metamorphic belts and gravel beaches or riverbeds.
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