 It is a soft mineral, with hardness to 3, a little less than that of calcite.The specific gravity, 5.63, is high, due to the copper content, djurleite is denser than the copper-iron sulfide bornite, but not as dense as the iron-arsenic sulfide arsenopyrite.Djurleite is grey, blue-black or black, with a black streak and a submetallic to metallic luster.