Chalcopyrite 

Chalcopyrite is a copper bearing mineral and is of high economic importance. The mineral has a brass-yellow colour to it and may sometimes be iridescent, resembling bornite. 

Chalcopyrite is found in South Africa, Namibia, Zimambwe, Botswana and Swaziland. 

Chemical Formular :   CuFeS2
Refractive Index :        Opaque
Hardness :                   3½ – 4 on the Mohs Scale
Crystal System :         Tetragonal