About the Crust of the Earth
The crust is the thinest layer of the earth. The crust is about 25 miles thick and and that's why the crust is light and brittle. The temperatures of the crust is about 870 degrees Celcius.
http://volcano.oregonstate.edu/vwdocs/vwlessons/lessons/Earths_layers/Earths_layers4.html