igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on Mohs scale, typically dark gray to black, dull luster, fine-grained aphanitic crystal structure, specific gravity around 2.8-3.0.
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Physical properties
Hardness of 6 on Mohs scale, typically dark gray to black, dull luster, fine-grained aphanitic crystal structure, specific gravity around 2.8-3.0.
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, railroad ballast, dimension stone, and in manufacturing rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins and forming vast volcanic provinces.
Field identification & locations
Identified by its dark color, heavy weight, and fine-grained texture; commonly found in volcanic regions and oceanic crusts worldwide.
