Original paper

Viaeneite, (Fe,Pb)4S8O, a new mineral with mixed sulphur valencies from Engis, Belgium

Kucha, Henryk; Osuch, Wladyslaw; Elsen, Jan

European Journal of Mineralogy Volume 8 Number 1 (1996), p. 93 - 102

21 references

published: Feb 22, 1996
manuscript accepted: Aug 29, 1995
manuscript received: Dec 6, 1994

DOI: 10.1127/ejm/8/1/0093

BibTeX file

ArtNo. ESP147050801011, Price: 29.00 €

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Abstract

Abstract Viaeneite, (Fe,Pb)4S8O, forms aggregates up to 4 mm in size. Associated minerals are pyrite, marcasite, melnikovite, sphalerite, galena, other Zn-Pb compounds with double sulfur valencies, goethite, zincian siderite, smithsonite and greigite. The mineral has a yellow colour, a distinct reflection pleochroism and is strongly anisotropic. Its R % in air, for λ = 546 nm, is 23.8-36.8 %, VHN200 = 252 kg/mm2 (range: 123-357), Dmeas = 3.8 ±0.1 g/cm3, Dcalc = 3.65 g/cm3. Microprobe analyses give (wt.%, average): Fe 42.37, Pb 4.02, Zn 0.05, Ni 0.20, As 0.17, S 49.74, O 3.69, total 100.24. The empirical formula (based on microprobe analyses) is: (Fe3.91 Pb0.10N10.02)4.03(S8.00As0.01 )8.01 O1.16· The sulphur is present in two valency combinations: disulphide, S22-, and thiosulphate, S2O32-, in the ratio 11:1. Viaeneite is monoclinic: a = 9.717 ± 0.008, b = 7.280 ± 0.006, c = 6.559 ± 0.007(Å) and β = 95.00° ± 0.03, V = 462.2 ± 0.8 Å3, Z = 2. The cell is probably primitive. The strongest XRD powder reflections are 3.43(5), 2.709(10), 2.419(8), 2.323(7), 1.920(6), 1.758(8), 1.595(5), 1.162(5), 1.092(5), 1.035(5), 0.9911(5) and 0.9576(7)(Å). The name is given in honour of Prof. W. Viaene, Katholieke Universiteit Leuven, Belgium.

Keywords

new mineralviaeneitesulphur valencythiosulphatedisulphide