igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness of 5-6 on the Mohs scale, typically dark gray to black in color, with a fine-grained aphanitic or vesicular texture and dull 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 5-6 on the Mohs scale, typically dark gray to black in color, with a fine-grained aphanitic or vesicular texture and dull 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, aggregate for concrete, road base, and crushed stone, as well as for making basalt fiber.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the world's ocean basins and forms massive geological formations like the Columbia River Flood Basalts.
Field identification & locations
Easily identified by its dark color, fine crystal structure, and frequently vesicular or spongy appearance containing gas cavities; found globally in volcanic regions.
