The thinnest layer of Earth's interior is the crust. It is the outermost layer and is made up of solid rock. The crust varies in thickness from about 5 kilometers (3 miles) beneath the ocean floor to about 70 kilometers (43 miles) beneath the continents.

What is the density of that layer:

The density of Earth's crust varies depending on the composition of the rocks. The continental crust is generally less dense than the oceanic crust. The average density of the continental crust is about 2.7 grams per cubic centimeter, while the average density of the oceanic crust is about 3 grams per cubic centimeter.