igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on the Mohs scale, typically dark gray to black in color, aphanitic to porphyritic texture, with dull to sub-metadioritic luster and high density.
Identified More igneous →
Explore Basalt in the encyclopedia →Identify your own rocks.
Get a report just like this from any photo, free.
Physical properties
Hardness of 6 on the Mohs scale, typically dark gray to black in color, aphanitic to porphyritic texture, with dull to sub-metadioritic luster and high density.
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
Used extensively in construction as crushed stone for road bases, railroad ballast, aggregate in concrete, and in stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust, making up most of the oceanic crust and forming massive regional flood basalt provinces.
Field identification & locations
Identify by its fine-grained dark matrix, often with visible olivine or pyroxene phenocrysts; widely distributed globally in volcanic regions.
