New data on sulphosalts from the hydrothermal siderite-type veins in the Spišsko-gemerské rudohorie Mts. (eastern Slovakia): 2. Jaskólskiite and associated sulphosalts from the Aurélia II vein near Rožňava

Abstract

New samples of jaskólskiite were recently collected at the Aurélia II siderite-type hydrothermal vein with sulphides near Rožňava, Spišsko-gemerské rudohorie Mts., Rožňava Co., Košice Region, Slovakia. It forms lead-gray, irregular aggregates up to 1.5 × 1 cm in size, which are enclosed in quartz-siderite gangue. Aggregates of jaskólskiite are consisting of individual, subhedral acicular crystals to 2 mm long, strongly replaced by younger bournonite and associated with Bi-rich jamesonite, tetrahedrite-(Fe), tintinaite, native bismuth and ullmannite. Significant variation of Cu (from 0.04 to 0.23 apfu) and Bi contents (from 0.32 to 0.77 apfu) was observed in studied sample. The average (n = 69 analyses) empirical formula of jaskólskiite from Rožňava-Aurélia vein based on Pb+Bi+Sb = 4 apfu is corresponding to Pb2.11Cu0.13(Sb1.42Bi0.47)1.89S5.14. Bi-rich jamesonite is the most common sulphosalt at the studied locality and it forms prismatic crystals up to 2 cm or irregular aggregates to 3 cm in size. The Bi content in jamesonite is ranging between 0.49 to 1.69 apfu. Bournonite is also common and two compositional types were distinguished. The first, dominant type is represented by Bi-rich bournonite (containing up to 0.14 apfu Bi). The second type of bournonite, represented by thin ribbons shows significant enrichment in As (reaching up to 0.49 apfu), but has only minor content of Bi (up to 0.08 apfu). Tintinaite is rare and its average (n = 9) empirical formula based on sum of all atoms = 63 apfu is corresponding to (Pb9.67Ag0.06)9.73(Cu2.55Fe0.40Zn0.07)3.02(Sb10.19Bi5.37)15.56S34.59Cl0.10.