igneous
Basalt Pebble
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, dark gray to black color, aphanitic texture with fine-grained mineral crystals, sub-conchoidal fracture, and high specific gravity.
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Physical properties
Hardness of 6 on the Mohs scale, dark gray to black color, aphanitic texture with fine-grained mineral crystals, sub-conchoidal fracture, and high specific gravity.
Formation & geological history
Formed from the rapid cooling of low-viscosity basaltic lava flows exposed at or very near the Earth's surface.
Uses & applications
Commonly used in construction aggregate, road base, railroad ballast, and landscaping.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins and forms extensive volcanic formations globally.
Field identification & locations
Identify in the field by its dark, heavy, fine-grained appearance, often found smoothed as river or beach pebbles due to water transport.
