Jaskolskiite, a new Pb-Cu-Sb-Bi sulfosalt from the Vena Deposit, Sweden

Jaskolskiite occurs in aggregates up to a few mm in diameter, intergrown with another Pb-Zu-Sb-Bi sulphosalt, native bismuth, galena, pyrrhotite and, rarely, antimony at the Vena Cu-Co mine in southern Bergslagen, Sweden. The average of 16 electron-microprobe analyses indicates a composition for jaskolskiite of Pb (sub 2.22) Cu (sub 0.19) Sb (sub 1.17) Bi (sub 0.62) S (sub 5) or, ideally, Pb (sub 2+x) Cu (sub x) (Sb,Bi) (sub 2-x) S (sub 5) , where Sb > Bi and x approx 0.2. The mineral corresponds with synthetic Pb (sub 2) Sb (sub 2) S (sub 5) of Wang and is a homologue of meneghinite. It is orthorhombic with space group Pbnm, a 11.33(1), b 19.871(2), c 4.100(1) A, Z = 4. The strongest XRD powder lines are 3.710(100), 2.970(80), 3.333(60), 2.761(60), 3.595(50), 2.751(50), 2.050(50) A. Jaskolskiite is lead-grey with metallic lustre and a dark grey streak, D (sub calc) 6.50 g/cm (super 3) , H. 4 (VHN ranges 165-179). In reflected light it is grey with greenish to yellowish tints due to reflection pleochroism; reflectances in air are 44.9, 37.2% (470 nm); 44.2, 36.3 (546 nm); 43.7, 36.1 (590 nm); 41.9, 34.8 (650 nm).