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 a-phanitic 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 a-phanitic or fine-grained crystal structure and dull luster.
Formation & geological history
Formed from the rapid cooling of low-viscosity basaltic lava exposed at or very near the Earth's surface.
Uses & applications
Used extensively in construction as crushed aggregate, railroad ballast, 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 forming major volcanic features like the Hawaiian Islands.
Field identification & locations
Identified by its dark, fine-grained appearance and heavy weight; found abundantly worldwide in volcanic regions and oceanic crust.
