igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness 6 on Mohs scale, dark gray to black color, fine-grained aphanitic texture, dull luster, 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, fine-grained aphanitic texture, dull luster, 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
Widely used in construction, crushed stone for road bases, railroad ballast, and manufacturing fiberglass.
Geological facts
Basalt is the most common rock type in the Earth's crust beneath the oceans and also forms extensive volcanic provinces on continents.
Field identification & locations
Identify by its dark, dense, fine-grained appearance, often containing small visible crystals of olivine or plagioclase.
