igneous
Basalt
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 texture, and a dull to sub-metallic luster.
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 with an aphanitic texture, and a dull to sub-metallic luster.
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
Widely used in construction as crushed aggregate for roads, railroad ballast, and in the production of stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins and forms dramatic geological formations like the Giant's Causeway.
Field identification & locations
Identify by its dark, fine-grained appearance and heavy weight relative to its size; common globally in volcanic provinces and oceanic crust.
