igneous
Dark, fine-grained pebble (likely basalt)
Basalt; exact identification requires closer examination
AI-generated identification · may be incorrectDark gray to black with a fine-grained, speckled surface and dull luster; likely composed mainly of plagioclase and pyroxene, possibly olivine. Typical basalt hardness is about 6 on the Mohs scale; crystals are too small to distinguish readily, and specific gravity is around 2.8–3.0.
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Physical properties
Dark gray to black with a fine-grained, speckled surface and dull luster; likely composed mainly of plagioclase and pyroxene, possibly olivine. Typical basalt hardness is about 6 on the Mohs scale; crystals are too small to distinguish readily, and specific gravity is around 2.8–3.0.
Formation & geological history
Likely formed when mafic lava cooled at or near Earth’s surface, then became rounded by weathering and transport. Basalt occurs from ancient to recent geological ages.
Uses & applications
Basalt is used as crushed aggregate, paving stone, and construction material; this small pebble is primarily suitable for collecting or decoration.
Geological facts
Basalt is one of Earth’s most common volcanic rocks and also forms much of the ocean floor.
Field identification & locations
The rounded shape suggests stream, beach, or glacial transport; dark color and fine grain are consistent with basalt, though the image alone cannot confirm it. Basalt is widespread worldwide, especially in volcanic regions.
