Igneous rock is one of the three main rock types, the others being sedimentary and metamorphic rock.
Igneous rocks are rocks formed from molten magma. The material is made liquid by the heat inside the Earth's mantle.
When magma comes out onto the surface of the Earth, it is called lava. Lava cools down to form rocks such as tuff and basalt. Intrusive rocks are made when the magma slowly cools to form rocks under the surface. Granite is one of these.
The word 'igneous' derives from the Latin word Ignis which is called fire in English.