igneous
Basalt
Extrusive Igneous Rock
AI-generated identification · may be incorrectHardness of 6 on Mohs scale, dark gray to black color, dull to sub-aphanitic luster, fine-grained aphanitic crystal structure, no prominent cleavage, specific gravity around 2.9.
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 Mohs scale, dark gray to black color, dull to sub-aphanitic luster, fine-grained aphanitic crystal structure, no prominent cleavage, specific gravity around 2.9.
Formation & geological history
Formed by the rapid cooling of low-viscosity lava rich in iron and magnesium exposed at or near the surface of a planet or moon.
Uses & applications
Used extensively in construction for crushed stone in road base, concrete aggregate, and manufacturing of rock wool insulation.
Geological facts
Basalt is the most common rock type in the Earth's oceanic crust and also makes up most of the volcanic islands worldwide.
Field identification & locations
Identify by its dark, heavy, fine-grained appearance; commonly found globally in volcanic regions, oceanic ridges, and flood basalt provinces.
