Nice small crystals of black Bournonite scattered on surface with crystals of Arsenopyrite. ARSENOPYRITE, FeAsS - Iron Arsenical Pyrite. Specimen from Pachapaqui Mine, Ancash Dept., Peru. Specimen is 6.3cm (2-1/2") wide x 5cm (2") deep x 3.8cm (1-1/2") high. Weight 0.31 lbs.