igneous
Basalt
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 to porphyritic texture 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 to porphyritic texture and dull luster.
Formation & geological history
Formed from the rapid cooling of low-viscosity, iron- and magnesium-rich lava exposed at or very near the Earth's surface.
Uses & applications
Commonly used in construction as crushed aggregate, road base, railroad ballast, and in the production of stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the ocean basins and also forms massive volcanic features like the Giant's Causeway.
Field identification & locations
Identify by its dark, fine-grained matrix, sometimes containing visible olivine or pyroxene phenocrysts; found globally in volcanic provinces.
