You're absolutely right! Igneous rocks are formed from hot liquid rock, which is called magma when it's underground and lava when it's erupted onto the Earth's surface. Here's what that means for igneous rocks:

* They are crystalline: As the magma or lava cools, the minerals within it crystallize, giving igneous rocks their characteristic texture.

* They can be intrusive or extrusive: Intrusive rocks form when magma cools slowly beneath the Earth's surface, allowing large crystals to form. Extrusive rocks form when lava cools quickly on the surface, resulting in smaller crystals or even a glassy texture.

* They come in a wide variety: The composition of the magma/lava determines the type of minerals that crystallize, leading to a huge range of igneous rock types, from granite to basalt.

Let me know if you'd like to know more about specific types of igneous rocks!