igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness 6 on Mohs scale, dark gray to black color, dull luster, microcrystalline or aphanitic structure, specific gravity around 2.9.
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Physical properties
Hardness 6 on Mohs scale, dark gray to black color, dull luster, microcrystalline or aphanitic structure, specific gravity around 2.9.
Formation & geological history
Formed from the rapid cooling of low-viscosity basaltic lava exposed at or very near the Earth's surface.
Uses & applications
Widely used in construction as crushed stone for road bases, concrete aggregate, and in the production of stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crustal portions underlying the ocean basins and also forms major continental flood basalt provinces.
Field identification & locations
Identify by its dark, fine-grained matrix and vesicular texture (gas cavities); found globally in volcanic regions and oceanic crust.
