igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, fine-grained aphanitic texture, and high density.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, fine-grained aphanitic texture, and high density.
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
Used heavily in construction as crushed aggregate, railroad ballast, and for manufacturing stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crustal portions underlying the ocean basins and forms massive geological features like the Giant's Causeway.
Field identification & locations
Identify in the field by its dark, dense, fine-grained appearance, often showing tiny visible mineral crystals or vesicles from trapped gas.
