 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 ( <unk> ) , <unk> ( <unk> ) , <unk> ( ( Co , Fe ) <unk> ) , and <unk> ( <unk> ) minerals . The mineral <unk> is similar to pyrite and occurs together with <unk> in the copper deposits of the Katanga Province . Upon contact with the atmosphere , weathering occurs and the sulfide minerals oxidize to form pink <unk> ( " cobalt glance " : <unk> ( AsO4 ) 2 · 8H2O ) and <unk> ( <unk> ) . 
