igneous
Basalt
Mafic extrusive igneous rock
AI-generated identification · may be incorrectHardness 6 on Mohs scale, dark gray to black color, dull luster, aphanitic crystal structure, specific gravity 2.8-3.0.
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 luster, aphanitic crystal structure, specific gravity 2.8-3.0.
Formation & geological history
Formed from the rapid cooling of low-viscosity, magnesium- and iron-rich lava flows at the Earth's surface.
Uses & applications
Used widely in construction as crushed stone for road bases, concrete aggregate, and in the production of rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's crust, making up most of the oceanic floor and large volcanic provinces like the Deccan Traps.
Field identification & locations
Identify by its fine-grained, dark texture and heavy weight; commonly found in volcanic regions and oceanic crusts worldwide.
