Summary:
- Magma cools to form igneous rocks.
- Two factors determine what type of rock forms.
- The composition of the magma determines if the rock is mafic, felsic, or intermediate.
- The rate of cooling determines the texture of the rock.
- Many mountain ranges are made of granite.
- Volcanoes are also found where you can't see them.
- Oceanic crust is mostly basalt and gabbro.
- The mantle is peridotite, a type of basalt.