igneous
Basalt
Extrusive igneous rock
AI-generated identification · may be incorrectHardness 6 on Mohs scale, dark gray to black color, dull luster, fine-grained 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, fine-grained aphanitic crystal structure, specific gravity 2.8-3.0.
Formation & geological history
Formed by 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 stone for road bases, concrete aggregate, and in the manufacturing of rock wool insulation.
Geological facts
Basalt is the most common rock type on Earth's crust, forming the majority of oceanic crust and major volcanic landforms like the Hawaiian Islands.
Field identification & locations
Identify in the field by its dark, dense, fine-grained matrix lacking visible crystals, commonly found in volcanic regions worldwide.
