igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, typically dark gray to black in color with an aphanitic or fine-grained texture and dull luster.
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Physical properties
Hardness of 6 on the Mohs scale, typically dark gray to black in color with an aphanitic or fine-grained texture 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
Widely used in construction for crushed stone, aggregate in concrete, road base, and historically for dimension stone and monuments.
Geological facts
Basalt is the most common rock type in the Earth's crustal portions underlying the ocean basins and also forms massive volcanic features like the Columbia River Plateau.
Field identification & locations
Identify by its dark, fine-grained appearance and heavy density. It is found abundantly worldwide in volcanic regions and oceanic crust.
