igneous
Rounded gray-green river pebble, probably basalt or greenstone
Likely fine-grained basalt; exact identification is uncertain from the photograph
AI-generated identification · may be incorrectA rounded, dull gray-green pebble with a fine-grained, weathered surface and possible pale mineral veins. If basalt, it is typically Mohs 5–6, with plagioclase and pyroxene; crystal structure is too fine to see, and specific gravity is roughly 2.8–3.0.
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Physical properties
A rounded, dull gray-green pebble with a fine-grained, weathered surface and possible pale mineral veins. If basalt, it is typically Mohs 5–6, with plagioclase and pyroxene; crystal structure is too fine to see, and specific gravity is roughly 2.8–3.0.
Formation & geological history
Likely formed as volcanic rock, then weathered and rounded during transport in water. The image cannot establish its age; volcanic rocks occur in Ethiopia’s Rift region, but the find location alone does not confirm this identification.
Uses & applications
Primarily a natural collectible or decorative pebble; basalt is also widely used as crushed aggregate and paving stone.
Geological facts
Its smooth shape is consistent with abrasion during transport, while the pale streaks may be mineral-filled cracks or surface marks.
Field identification & locations
Look for a dense, fine-grained interior and no visible sand-sized grains; a fresh broken surface or hardness/streak tests would help distinguish basalt from other dark rocks. Similar pebbles are common in streams and gravel deposits.
