Rocks that form by the cooling and solidification of magma or lava.
Rocks that form by the cooling and solidification of magma or lava. Igneous rocks are the most common of the three types of rock on Earth, sedimentary and metamorphic rocks making up only about one-twentieth of the crust. Extrusive igneous rocks are formed when lava cools at the surface, while intrusive igneous rocks are those that cool and form underground.
Igneous rocks are the most common of the three types of rock on Earth, sedimentary and metamorphic rocks making up only about one-twentieth of the crust. Extrusive igneous rocks are formed when lava cools at the surface, while intrusive igneous rocks are those that cool and form underground.