igneous
Rounded dark pebble, likely basalt
Basalt (tentative identification; exact rock type cannot be confirmed from the image)
AI-generated identification · may be incorrectDark gray-green to brown, fine-grained and dull, with a rounded, weathered surface. Basalt typically has Mohs hardness 5–6, a fine-grained texture, and specific gravity around 2.8–3.0.
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Physical properties
Dark gray-green to brown, fine-grained and dull, with a rounded, weathered surface. Basalt typically has Mohs hardness 5–6, a fine-grained texture, and specific gravity around 2.8–3.0.
Formation & geological history
If basalt, it formed when iron- and magnesium-rich lava cooled quickly at or near Earth’s surface; basalt occurs from ancient to recent geological ages. Its rounded shape likely resulted from transport and abrasion by water or sediment.
Uses & applications
Basalt is widely used as crushed aggregate, paving stone, and construction material; this small pebble has mainly decorative or educational value.
Geological facts
Basalt is one of Earth’s most abundant volcanic rocks and makes up much of the ocean floor.
Field identification & locations
Look for a dense, dark, fine-grained rock, sometimes with tiny crystals or gas-bubble holes; confirm identification by inspecting a fresh break, since several dark rocks can look similar. Basalt is common in volcanic regions and river or beach gravels.
