igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on Mohs scale, dark gray to black color, aphanitic (fine-grained) texture, dull luster, and high specific gravity (approx. 2.8-3.0).
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Physical properties
Hardness of 6 on Mohs scale, dark gray to black color, aphanitic (fine-grained) texture, dull luster, and high specific gravity (approx. 2.8-3.0).
Formation & geological history
Formed from the rapid cooling of low-viscosity basaltic lava exposed at or very near the Earth's surface, common in volcanic regions worldwide.
Uses & applications
Widely used in construction as crushed stone for road bases, concrete aggregate, and manufacturing dimension stone.
Geological facts
Basalt is the most common rock type in the Earth's crustal portions underlying the ocean basins and also forms extensive continental flood basalts.
Field identification & locations
Identify in the field by its dark, fine-grained matrix, sometimes displaying vesicular holes from trapped gas bubbles during cooling.
