 Cobalt in compound form occurs as a minor component of copper and nickel minerals . It is the major metallic component in combination with sulfur and arsenic in the sulfidic cobaltite ( CoAsS ) , safflorite ( CoAs2 ) , glaucodot ( ( Co , Fe ) AsS ) , and skutterudite ( CoAs3 ) minerals . The mineral cattierite is similar to pyrite and occurs together with vaesite in the copper deposits of the Katanga Province . Upon contact with the atmosphere , weathering occurs and the sulfide minerals oxidize to form pink erythrite ( " cobalt glance " : Co3 ( AsO4 ) 2 · 8H2O ) and spherocobaltite ( CoCO3 ) . 
