igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, dull luster, aphanitic texture with microscopic crystals, and high specific gravity.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, dull luster, aphanitic texture with microscopic crystals, and high specific gravity.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava flows at the Earth's surface.
Uses & applications
Used extensively in construction as crushed stone for road bases, concrete aggregate, and dimension stone.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins and forming major volcanic features like the Hawaiian Islands.
Field identification & locations
Identify in the field by its fine-grained, dark-colored appearance and dense, heavy feel. Common globally in volcanic regions.
