igneous
Basalt
Extrusive igneous rock primarily composed of plagioclase and pyroxene
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark black to gray color, dull to sub-to-submetallic luster, fine-grained aphanitic crystal structure, and high specific gravity.
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Physical properties
Hardness of 6 on the Mohs scale, dark black to gray color, dull to sub-to-submetallic luster, fine-grained aphanitic crystal structure, and high specific gravity.
Formation & geological history
Formed from the rapid cooling of low-viscosity basaltic lava exposed at or near the surface of a planet or moon.
Uses & applications
Used extensively in construction as crushed stone for road bases, concrete aggregate, and manufacturing of rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crustal portions underlying the ocean basins and forms massive geological features like the Columbia River Flood Basalts.
Field identification & locations
Identify by its dark, dense, fine-grained matrix often showing vesicular gas cavities; found globally in volcanic regions and oceanic crust.
