This is an image from the Mars rover, Curiosity, showing Mount Sharp. Why does Mars have this rusty red-orange colour? Yes, because it is rusting; the colour is caused by iron (III)oxide which you can also simply call rust.

This is an image from the Mars rover, Curiosity, showing Mount Sharp. Why does Mars have this rusty red-orange colour? Yes, because it is rusting; the colour is caused by iron (III)oxide which you can also simply call rust.