Left (top): Ag-rich chalcopyrite in contact with gustavite (Ag-containing Pb-Bi-sulfide) changes its reflection...Fizélyite often weak, olive and blue lamellar Gustavite Chalcopyrite Mooihoekite slight medium grey...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, |