igneous
Basalt Pebble
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, typically dark gray to black in color, with an aphanitic and fine-grained crystal structure. It possesses a dull luster and lacks prominent cleavage.
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Physical properties
Hardness of 6 on the Mohs scale, typically dark gray to black in color, with an aphanitic and fine-grained crystal structure. It possesses a dull luster and lacks prominent cleavage.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava exposed at or very near the Earth's surface.
Uses & applications
Commonly used in construction aggregate, road base materials, railroad ballast, and decorative landscaping.
Geological facts
Basalt is the most common rock type in the Earth's oceanic crust and also forms extensive continental flood basalt provinces.
Field identification & locations
Easily identified in the field by its dark, fine-grained appearance and heavy, dense feel. It is found globally in volcanic regions and river beds.
