igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, dull luster, aphanitic (fine-grained) crystal structure, specific gravity around 2.8-3.0.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, dull luster, aphanitic (fine-grained) 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 surface of a planet or moon.
Uses & applications
Widely used in construction for crushed stone, road base, concrete aggregate, and manufacturing of stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins and makes up most of the volcanic islands.
Field identification & locations
Identify by its dark, fine-grained groundmass, sometimes containing visible olivine or pyroxene phenocrysts; found globally in volcanic regions and flood basalt provinces.
