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 near the Earth's surface, often from volcanic eruptions.
Uses & applications
Widely used in construction for crushed stone, railroad ballast, aggregate in concrete, and manufacturing rock 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 formations like the Giant's Causeway.
Field identification & locations
Identify by its dense dark color, fine-grained texture lacking visible crystals, and frequent occurrence in volcanic regions.
