igneous
Basalt
Mafic extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, fine-grained aphanitic texture, dull luster.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, fine-grained aphanitic texture, dull luster.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava flows at the Earth's surface.
Uses & applications
Used heavily in construction as crushed stone for road bases, concrete aggregate, and railroad ballast.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins and forming much of the moon's maria.
Field identification & locations
Identify by its dark color, fine grain size, and dense, heavy feel. Found globally in volcanic regions and oceanic crust.
