igneous
Basalt
Extrusive mafic igneous rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, typically dark gray to black in color, with an aphanitic or fine-grained texture and dull luster.
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Physical properties
Hardness of 6 on the Mohs scale, typically dark gray to black in color, with an aphanitic or fine-grained texture and dull luster.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava flows at the Earth's surface.
Uses & applications
Widely used 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 volcanic structures like the Giant's Causeway.
Field identification & locations
Identified by its dark color, fine-grained groundmass, and heavy density; found abundantly in volcanic regions worldwide.
