igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness 6 on Mohs scale, dark gray to black color, aphanitic to porphyritic texture, dull luster, specific gravity 2.8-3.0.
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Physical properties
Hardness 6 on Mohs scale, dark gray to black color, aphanitic to porphyritic texture, dull luster, specific gravity 2.8-3.0.
Formation & geological history
Formed from the rapid cooling of low-viscosity lava rich in magnesium and iron exposed at or very near the surface of a planet or moon.
Uses & applications
Used extensively in construction as crushed stone for road bases, concrete aggregate, and manufacturing 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 forms dramatic geological formations like the Giant's Causeway.
Field identification & locations
Identify by its dark, fine-grained groundmass, sometimes containing small visible crystals of olivine or plagioclase; found globally in volcanic provinces.
