1. Oceanic Crust: This type of crust is found beneath the ocean basins and is primarily composed of basalt and gabbro, which are dark, dense, and rich in magnesium and iron. It is relatively thin, typically around 5-10 kilometers thick.

2. Continental Crust: This type of crust makes up the continents and is generally thicker and less dense than oceanic crust. It is made up of a wider variety of rock types, including granite, diorite, and gneiss. Continental crust can reach thicknesses of up to 70 kilometers.