igneous
Basalt
Extrusive Igneous Rock (Mafic)
AI-generated identification · may be incorrectHardness 6 on Mohs scale, dark gray to black color, dull luster, aphanitic to microcrystalline texture with fine grains, specific gravity 2.8-3.0.
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Physical properties
Hardness 6 on Mohs scale, dark gray to black color, dull luster, aphanitic to microcrystalline texture with fine grains, specific gravity 2.8-3.0.
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
Widely used in construction for crushed stone, aggregate in concrete, road base, and manufacturing of rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's oceanic crust and also makes up the vast majority of volcanic islands like Hawaii.
Field identification & locations
Identify by its dark, fine-grained appearance and heavy weight; found globally in volcanic regions, oceanic ridges, and flood basalt provinces.
