various Cu-Fe-S-phases (e.g., chalcopyrite bornite, cubanite, and others) in a bi-directional redox reaction...Penroseite polysynthetic Carrollite Cosalite yes Cubanite Shandite yes Diaphorite Isocubanite yes Bravoite...grey); Himmelsfürst Mine, Brand-Erbisdorf, Freiberg District, Erzgebirge, Sachsen, Germany (sample: Seifert);...quartz (dark grey); New Bullfrog Mine, Bullfrog District, Nye Co., Nevada, USA (sample: Witzke); PPL If...placers Kaietur Falls, Potaro River, Kangaruma District, Potaro-Siparuni Region, Guyana Chalcopyrite, |