igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, dull luster, and vesicular texture with numerous gas cavities.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, dull luster, and vesicular texture with numerous gas cavities.
Formation & geological history
Formed from the rapid cooling of low-viscosity lava rich in magnesium and iron exposed at or very near the Earth's surface.
Uses & applications
Used extensively in construction, crushed stone for road bases, and as aggregate in concrete.
Geological facts
Basalt is the most common rock type in the Earth's oceanic crust and also forms extensive continental flood basalts.
Field identification & locations
Easily identified by its dark, fine-grained matrix and characteristic vesicular or frothy cavities created by trapped volcanic gas bubbles.
