Crust   The uppermost 5-70 km of the earth. There are two types of crust: continental and oceanic. Continental crust ranges from 10-70 km thick and has a composition approximating that of granite. Oceanic crust, on the other hand, is approximately 5 km thick and has a composition similar to basalt, making it significantly denser than continental crust.

Used in the following modules: Earth Structure, Minerals I, Minerals II, Minerals III, Plate Tectonics I, Plate Tectonics II, The Rock Cycle