igneous
Basalt
Extrusive mafic igneous rock
AI-generated identification · may be incorrectHardness 6 on Mohs scale, dark gray to black color, fine-grained aphanitic texture, dull to submetallic luster, specific gravity 2.8-3.0.
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Physical properties
Hardness 6 on Mohs scale, dark gray to black color, fine-grained aphanitic texture, dull to submetallic luster, specific gravity 2.8-3.0.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava flows on or near the Earth's surface.
Uses & applications
Widely used in construction for crushed stone, aggregate in concrete, road base, and manufactured stone products.
Geological facts
Basalt is the most common rock type in the Earth's crust, underlying most ocean basins and forming major volcanic features like the Columbia River Plateaus.
Field identification & locations
Identify by its dark, fine-grained matrix and heavy weight; commonly found in volcanic regions worldwide.
