igneous
Basalt
Mafic 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 or fine-grained 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 6 on the Mohs scale, typically dark gray to black in color, with an aphanitic or fine-grained texture and dull luster.
Formation & geological history
Formed from the rapid cooling of low-viscosity basaltic lava exposed at or near the Earth's surface, often originating from volcanic hotspots or divergent plate boundaries.
Uses & applications
Widely used in construction as crushed stone for road bases, railroad ballast, and aggregate in concrete, as well as in manufacturing stone wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust underlying the oceans and also makes up the vast majority of volcanic islands like Hawaii.
Field identification & locations
Identify in the field by its dark color, heavy weight, and fine-grained matrix where individual crystals are rarely visible without magnification.
