igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness 6 on Mohs scale, dark gray to black color, aphanitic to porphyritic texture, dull luster, specific gravity 2.8-3.0.
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Physical properties
Hardness 6 on Mohs scale, dark gray to black color, aphanitic to porphyritic texture, dull luster, specific gravity 2.8-3.0.
Formation & geological history
Formed from the rapid cooling of low-viscosity basaltic lava exposed at or very near the Earth's surface.
Uses & applications
Used in construction, road aggregate, railroad ballast, and manufacturing of stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crustal portions underlying the ocean basins and also forms massive volcanic features like the Columbia River Plateaus.
Field identification & locations
Identify by its dark, fine-grained matrix often containing visible plagioclase or olivine phenocrysts. Found globally in volcanic regions.
