igneous
Basalt
Mafic extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, typically dark gray to black in color, with an aphanitic or fine-grained crystal structure and dull luster.
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Physical properties
Hardness of 6 on the Mohs scale, typically dark gray to black in color, with an aphanitic or fine-grained crystal structure and dull luster.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava exposed at or very near the Earth's surface.
Uses & applications
Widely used in construction as crushed stone for road bases, railroad ballast, and aggregate in concrete production.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins and forms massive geological features like the Giant's Causeway.
Field identification & locations
Identify by its dark color, heavy weight, and fine-grained texture lacking visible crystals. Commonly found in volcanic regions worldwide.
