igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness 6 on Mohs scale, dark gray to black color, dull to sub-aphanitic luster, fine-grained aphanitic crystal structure.
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 6 on Mohs scale, dark gray to black color, dull to sub-aphanitic luster, fine-grained aphanitic crystal structure.
Formation & geological history
Formed from the rapid cooling of low-viscosity basaltic lava exposed at or very near the Earth's surface.
Uses & applications
Widely used in construction as crushed aggregate, railroad ballast, and for manufacturing stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crustal portions underlying the ocean basins and forms much of the lunar maria.
Field identification & locations
Identify by its dark, fine-grained matrix, heavy weight, and common occurrence in volcanic provinces worldwide.
