For some minerals, color is directly realted to one of the major elements and can be characteristic and serve as a means of identification. Malichite is always green, azurite is always blue, and rhondonite is always red or pink.

Most metallic minerals color is constant such as the brass-yellow of chalcopyrite and the copper-red or niccolite. These minerals may also tarnish which is espeically true of the mineral bornite. It is called the "peacock ore" because of the blue-velvet tarnish that develops on the surface.