igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness 6 on Mohs scale, dark gray to black color, aphanitic 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 texture, dull luster, specific gravity 2.8-3.0.
Formation & geological history
Formed from the rapid cooling of low-viscosity lava rich in iron and magnesium exposed at or very near the Earth's surface.
Uses & applications
Used widely in construction as crushed stone for road bases, concrete aggregate, and in the manufacturing of rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crustal portions underlying the ocean basins and forms famous formations like the Giant's Causeway.
Field identification & locations
Identify by its dark, fine-grained appearance and heavy weight. Found globally in volcanic provinces and oceanic crusts.
