igneous
Dark fine-grained pebble, possibly basalt
Basalt (tentative identification)
AI-generated identification · may be incorrectRounded, dark gray-green pebble with a dull surface and lighter weathered patches. Basalt is typically fine-grained, Mohs 5–6, and composed mainly of plagioclase and pyroxene; crystal structure is not visible here.
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Physical properties
Rounded, dark gray-green pebble with a dull surface and lighter weathered patches. Basalt is typically fine-grained, Mohs 5–6, and composed mainly of plagioclase and pyroxene; crystal structure is not visible here.
Formation & geological history
If basalt, it formed when mafic lava cooled rapidly at or near Earth’s surface; the pebble’s rounded shape likely developed through transport and abrasion. Its age cannot be determined from the image.
Uses & applications
Commonly used as crushed aggregate, road stone, and building stone; this small pebble has little commercial value but may be collected or used decoratively.
Geological facts
Basalt is among Earth’s most abundant volcanic rocks and also forms much of the ocean floor.
Field identification & locations
A dark, dense pebble with fine texture and no obvious layering can suggest basalt, but the photo cannot confirm the identification. Basalt occurs worldwide, especially in volcanic regions and river or beach gravels.
