igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness 6 on Mohs scale; dark grey to black color; fine-grained aphanitic texture; dull luster; specific gravity around 2.9.
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Physical properties
Hardness 6 on Mohs scale; dark grey to black color; fine-grained aphanitic texture; dull luster; specific gravity around 2.9.
Formation & geological history
Formed from the rapid cooling of low-viscosity basaltic lava exposed at or very near the Earth's surface.
Uses & applications
Widely used in construction as crushed aggregate, road base, and dimension stone, as well as in manufacturing rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crustal portions underlying the ocean basins and forms massive features like the Columbia River Flood Basalts.
Field identification & locations
Identify by its dark, fine-grained appearance, dense weight, and occasional vesicular texture; found worldwide in volcanic regions.
