igneous
Basalt
Mafic extrusive igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, typically dark gray to black in color, with a-phanitic or glassy luster and fine-grained crystal structure.
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Physical properties
Hardness of 6 on the Mohs scale, typically dark gray to black in color, with a-phanitic or glassy luster and fine-grained crystal structure.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava exposed at or very near the Earth's surface.
Uses & applications
Extensively used in construction as crushed aggregate for roads, railroad ballast, 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 also forms massive geological formations like the Columbia River Flood Basalts.
Field identification & locations
Identified by its dark color, fine-grained texture, and dense weight, commonly found in volcanic regions and oceanic crusts worldwide.
