igneous
Basalt
Extrusive igneous rock (Mafic)
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, typically dark gray to black in color, fine-grained aphanitic texture with prominent vesicular holes, specific gravity around 2.9.
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Physical properties
Hardness of 6 on the Mohs scale, typically dark gray to black in color, fine-grained aphanitic texture with prominent vesicular holes, specific gravity around 2.9.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava flows exposed at or very near the Earth's surface.
Uses & applications
Used extensively in construction as crushed stone, aggregate in concrete, road base, and historically for paving stones.
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 by its dark color, heavy weight, and vesicular or smooth exterior; commonly found in volcanic regions worldwide.
