igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness 6 on Mohs scale, dark gray to black in color, dull to sub-aphanitic luster, fine-grained aphanitic crystal structure with visible vesicular cavities.
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Physical properties
Hardness 6 on Mohs scale, dark gray to black in color, dull to sub-aphanitic luster, fine-grained aphanitic crystal structure with visible vesicular cavities.
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 in the production of rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust, primarily making up the ocean floors and major volcanic islands like Hawaii.
Field identification & locations
Identify by its dark, heavy nature, fine-grained texture, and frequent presence of gas bubble holes; found globally in volcanic regions.
