igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on Mohs scale, typically dark gray to black in color, aphanitic texture with fine-grained minerals, and dull luster.
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Physical properties
Hardness of 6 on Mohs scale, typically dark gray to black in color, aphanitic texture with fine-grained minerals, and dull luster.
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 heavily in construction as crushed stone for road bases, concrete aggregate, and in the production of stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's oceanic crust and also forms extensive continental flood basalts.
Field identification & locations
Identify in the field by its dark color, fine-grained texture, and sometimes vesicular nature from trapped gas bubbles.
