igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, dull luster, microcrystalline or aphanitic texture with fine-grained minerals.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, dull luster, microcrystalline or aphanitic texture with fine-grained minerals.
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 for roads, railroad ballast, and in the manufacture of rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's oceanic crust and also makes up major volcanic features on the Moon and Mars.
Field identification & locations
Identify by its dark color, heavy weight, and fine-grained texture; commonly found in volcanic regions and ancient lava flows worldwide.
