igneous
Basalt
Mafic extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, aphanitic texture with microscopic crystals, dull to sub-vitreous luster.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, aphanitic texture with microscopic crystals, dull to sub-vitreous luster.
Formation & geological history
Formed from the rapid cooling of low-viscosity, iron and magnesium-rich lava flows on the Earth's surface.
Uses & applications
Widely used in construction aggregate, railroad ballast, road base, and crushed stone.
Geological facts
Basalt is the most common rock type in the Earth's crustal portions underlying the ocean basins.
Field identification & locations
Identify by its dark, fine-grained appearance, heavy density, and occasional vesicular texture from trapped gas bubbles.
