igneous
Basalt
Extrusive igneous rock primarily composed of plagioclase and pyroxene
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, dull luster, fine-grained aphanitic texture with microscopic crystals.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, dull luster, fine-grained aphanitic texture with microscopic crystals.
Formation & geological history
Formed from the rapid cooling of low-viscosity basaltic lava exposed at or very near the Earth's surface.
Uses & applications
Widely used in construction as crushed aggregate, railroad ballast, dimension stone, and in manufacturing 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 formations like the Columbia River Basalts.
Field identification & locations
Identify by its dark, fine-grained appearance and heavy density; commonly found in volcanic regions and oceanic crusts worldwide.
