igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on Mohs scale, dark gray to black color, aphanitic texture, subconchoidal fracture, and specific gravity around 2.9.
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Physical properties
Hardness of 6 on Mohs scale, dark gray to black color, aphanitic texture, subconchoidal fracture, and 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
Used extensively in construction as crushed stone for road bases, concrete aggregate, and in the production 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 massive volcanic features like the Giant's Causeway.
Field identification & locations
Identify by its dark, fine-grained appearance and heavy weight. Found worldwide in volcanic provinces and oceanic crust.
