metamorphic
Weathered greenstone pebble
Likely metabasalt (chlorite–actinolite-rich greenschist); exact identification requires close examination
AI-generated identification · may be incorrectFine-grained, dark green-gray, dull to subtly sparkly surface; rounded by weathering or water. Likely Mohs hardness 5–6, with no obvious cleavage; composition and crystal structure cannot be confirmed from the image.
Identified More metamorphic →
Explore Weathered greenstone pebble in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Fine-grained, dark green-gray, dull to subtly sparkly surface; rounded by weathering or water. Likely Mohs hardness 5–6, with no obvious cleavage; composition and crystal structure cannot be confirmed from the image.
Formation & geological history
Probably basalt altered by low-grade metamorphism, producing a greenschist-facies rock. Its age and specific formation environment cannot be determined from appearance alone.
Uses & applications
Commonly used as landscaping or decorative stone and collected as a field specimen; this small pebble has little commercial value.
Geological facts
Greenstone is a descriptive term for altered mafic rocks, not a single mineral or precisely defined rock type.
Field identification & locations
Its compact, fine-grained texture and green-gray color are consistent with greenstone, but similar-looking rocks include serpentinite and other altered volcanic rocks. Found in metamorphic belts and glacial or stream deposits; a fresh broken surface and mineral tests would help identify it.
More like this
