igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, dull luster, fine-grained aphanitic crystal structure, and high specific gravity.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, dull luster, fine-grained aphanitic crystal structure, and high specific gravity.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava flows exposed at or near the Earth's surface.
Uses & applications
Utilized widely in construction as crushed stone for road bases, concrete aggregate, and in the production of rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins and forms famous columns like the Giant's Causeway.
Field identification & locations
Identified easily by its dark, heavy, fine-grained texture; commonly found in volcanic regions and coastal areas like Maine.
