igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on Mohs scale; dark gray to black color; fine-grained aphanitic luster; composed mainly of plagioclase and pyroxene.
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Physical properties
Hardness of 6 on Mohs scale; dark gray to black color; fine-grained aphanitic luster; composed mainly of plagioclase and pyroxene.
Formation & geological history
Formed from the rapid cooling of low-viscosity lava rich in iron and magnesium exposed at or near the Earth's surface.
Uses & applications
Commonly used in construction as crushed aggregate, railroad ballast, and dimension stone.
Geological facts
Basalt is the most common rock type in the Earth's crust, making up most of the ocean floor and large volcanic provinces like the Columbia River Plateaus.
Field identification & locations
Identify by its dark, dense, fine-grained appearance, often found in volcanic regions and oceanic crusts worldwide.
