Conversation so far:
Describe the oceanic crust.
Oceanic crust is about 6 km (4 miles) thick. It is composed of several layers, not including the overlying sediment.
What are the main layers in the oceanic crust?
The crust and the solid mantle layer together constitute oceanic lithosphere. Oceanic crust is primarily composed of mafic rocks, or sima, which is rich in iron and magnesium.

Question: How does it differ from the continental crust
Self-contained rewrite: How does the oceanic crust differ from the continental crust?