igneous
Rounded pebble, likely greenstone or altered basalt
Likely chlorite- or epidote-altered basalt; identification is uncertain from the image alone
AI-generated identification · may be incorrectOlive-gray, smooth and rounded with a dull to slightly waxy surface; likely fine-grained, with hardness around 5–6 and no visible cleavage. Exact mineral composition and density cannot be determined visually.
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Physical properties
Olive-gray, smooth and rounded with a dull to slightly waxy surface; likely fine-grained, with hardness around 5–6 and no visible cleavage. Exact mineral composition and density cannot be determined visually.
Formation & geological history
If basaltic, it formed from rapidly cooled lava and was later altered by fluids; water or sediment abrasion rounded it. Its age and original source are not identifiable from the photo.
Uses & applications
Primarily a natural collectible or decorative pebble; comparable rock is sometimes used as aggregate or landscaping stone.
Geological facts
Greenstone is a broad field term for altered, green-hued volcanic rock, commonly colored by chlorite, epidote, or actinolite.
Field identification & locations
The rounded shape and muted green-brown color fit a water-worn pebble, but a fresh broken surface or hardness and streak tests would help distinguish basalt from other rocks. Greenstone and basalt occur widely worldwide.
