igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, dull luster, aphanitic crystal structure, specific gravity around 2.8-3.0.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, dull luster, aphanitic crystal structure, specific gravity around 2.8-3.0.
Formation & geological history
Formed from the rapid cooling of low-viscosity lava rich in iron and magnesium exposed at or very near the Earth's surface.
Uses & applications
Used extensively in construction as crushed stone for road bases, railroad ballast, and aggregate in concrete.
Geological facts
Basalt is the most common rock type in the Earth's crustal portions underlying the ocean basins and also forms massive geological features like the Columbia River Basalts.
Field identification & locations
Easily identified by its fine-grained, dark-colored matrix and heavy weight; widely distributed across volcanic regions worldwide.
