igneous
Basalt
Mafic extrusive igneous rock
AI-generated identification · may be incorrectHardness 6 on Mohs scale; dark gray to black color; fine-grained, aphanitic texture; dull to sub-vitreous luster.
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Physical properties
Hardness 6 on Mohs scale; dark gray to black color; fine-grained, aphanitic texture; dull to sub-vitreous luster.
Formation & geological history
Formed from the rapid cooling of low-viscosity basaltic lava flows exposed at or very near the Earth's surface.
Uses & applications
Used extensively in construction as crushed aggregate for roads, railroad ballast, 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 makes up extensive volcanic formations on the Moon and Mars.
Field identification & locations
Identify by its dark, dense, fine-grained appearance and frequent vesicular textures; found worldwide in volcanic regions.
