More specifically, the Earth's crust is composed of two main types of rock:

* Continental crust: This is the thicker, less dense crust that makes up the continents. It is primarily composed of igneous and metamorphic rocks, with some sedimentary rocks.

* Oceanic crust: This is the thinner, denser crust that underlies the ocean basins. It is mostly composed of basalt, a type of volcanic rock, with a layer of sediment on top.

So, while "rock" is the general term for crustal material, you can be more specific depending on the context and the type of crust you are referring to.