igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness 6 on Mohs scale, dark gray to black color, dull luster, aphanitic to porphyritic crystal structure, specific gravity around 2.9.
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Physical properties
Hardness 6 on Mohs scale, dark gray to black color, dull luster, aphanitic to porphyritic crystal structure, specific gravity around 2.9.
Formation & geological history
Formed from the rapid cooling of low-viscosity basaltic lava exposed at or very near the Earth's surface, often from volcanic eruptions.
Uses & applications
Widely used in construction as crushed stone for roadbeds, aggregate in concrete, and in the manufacturing of rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins and forms massive geological features like the Columbia River Flood Basalts.
Field identification & locations
Identified by its fine-grained, dark-colored appearance and often vesicular texture from trapped gas bubbles; found globally in volcanic regions.
