igneous
Basalt
Mafic extrusive igneous rock
AI-generated identification · may be incorrectHardness 6 on Mohs scale, dark gray to black color, aphanitic to porphyritic texture, 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, specific gravity 2.8-3.0.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava flows at the Earth's surface.
Uses & applications
Used in construction as crushed aggregate, railroad ballast, and dimension stone, as well as in rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crustal portions of ocean basins and forms massive geological features like the Columbia River Plateaus.
Field identification & locations
Identify by its dark, fine-grained appearance, heavy weight, and occasional vesicular texture from trapped gas bubbles.
