There are two main types of igneous rocks:

* Intrusive igneous rocks: These form when magma cools and solidifies below the Earth's surface. They cool slowly, allowing large crystals to form, giving them a coarse-grained texture. Examples include granite and gabbro.

* Extrusive igneous rocks: These form when magma erupts onto the Earth's surface as lava and cools and solidifies. They cool quickly, resulting in small crystals or even a glassy texture. Examples include basalt and rhyolite.