Changing the color of a cube

Hey guy what is the reason why I can't change the color of this cube?
It doesn't let me select the color picker tool under the default Diffuse component

 

You have to apply a material to it first. The default is just that: the default.

 

Thanks for the reply Schneider21

So I can only change the color with a material?

 

This tutorial may help: http://unity3d.com/learn/tutorials/modules/beginner/graphics/materials