
sedimentary
Rounded gray-brown pebble
Indeterminate; likely weathered quartz-rich sandstone or fine-grained volcanic rock
AI-generated identification · may be incorrectDark gray-brown, dull to slightly earthy luster, fine-grained and strongly rounded; hardness approximately 5–7 Mohs depending on composition. No visible crystals, cleavage, or diagnostic banding can be resolved from the image; specific gravity is likely about 2.5–2.8.
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Physical properties
Dark gray-brown, dull to slightly earthy luster, fine-grained and strongly rounded; hardness approximately 5–7 Mohs depending on composition. No visible crystals, cleavage, or diagnostic banding can be resolved from the image; specific gravity is likely about 2.5–2.8.
Formation & geological history
Probably a naturally water-worn clast from a stream, beach, or gravel deposit; its geological age cannot be determined visually. The smooth shape reflects prolonged abrasion and weathering.
Uses & applications
Commonly used as a decorative pebble, landscaping stone, craft material, or specimen; no significant jewelry or industrial value is evident.
Geological facts
The surface appears naturally weathered rather than polished, though the photograph alone cannot exclude light human smoothing. A streak, hardness test, and fresh broken surface would be needed for confident identification.
Field identification & locations
Look for grain texture, reaction to dilute hydrochloric acid, and whether it scratches glass; quartz-rich rock scratches glass, while carbonate rock fizzes. Common worldwide in river and glacial gravels.
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