Studies of specimens from Falun, Sweden, reported to contain the two minerals weibullite and wittite have established at least three selenium-rich bismuth–lead sulphosalts of similar chemistry. A nomenclature is proposed in which two of the minerals retain the old names weibullite and wittite, while the third is given the new name nordströmite. Weibullite, Ag0.32Pb5.09Bi8.55Se6.08S11.92, is orthorhombic Pnma with a = 53.68, b = 4.11, c = 15.40Å; nordströmite, CuPb3Bi7(Se4,S10), is monoclinic P21/m with a = 17.97, b = 4.11, c = 17.62Å and β = 94.30°. Wittite, Pb0.3541Bi0.4366(Se0.2026,S0.7974), is monoclinic with two lattices. The sub-cells of these two lattices are: lattice A, P2/m, a = 4.19, b = 4.08, c; = 15.56Å, β = 101.35°; lattice B, C2/m, a = 7.21, b = 4.08, c = 15.50Å, β = 98.75°. They are virtually identical to those found in cannizzarite.

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