Lillianites and andorites: new life for the oldest homologous series of sulfosalts

Abstract

The current state of the lillianite homologous series is presented, with its two branches À the lillianite branch of the predominantly Pb-Bi-Ag sulfosalts and the andorite branch of predominantly Pb-Sb-Ag sulfosalts. Both the natural and synthetic members are discussed, especially from the structural and compositional point of view and the related, chemically distinct and structurally more complicated members of the series are described. A number of new published, or hitherto unpublished observations is given, together with fairly exhaustive tables of data. Relationships between the complex structures of different 'andorite' species and principal structural features of 'oversubstituted' As-Sb and Bi-Sb species are discussed. Contrary to many studies of this subject, synthetic phases form an integral part of the paper. It is concluded that research in this long-known homologous series still supplies new interesting phases, especially in the fields of synthetic products and in its andorite branch.

Lillianite homologues from Kutná Hora ore district, Czech Republic: a case of large-scale Sb for Bi substitution

“…The octahedra of adjacent, mirrorrelated layers are replaced by bi-capped trigonal coordination prisms of PbS 6+2 with the Pb atoms positioned on the mirror planes (Otto and Strunz 1968). Detailed description of the series was provided by Makovicky and Topa (2014).…”

“…(2) Bi 3+ ↔ Sb 3+ substitution is proposed in this paper to be expressed as a superscript past the phase symbol. The Bi-Sb substitution is expressed in terms of Bi/(Bi + Sb) atomic ratio multiplied by 100, an ideal gustavite with no Sb being 4 Gus (Makovicky and Topa 2014). Natural antimonian lillianite homologues are known only for N = 4 ( 4,4 L) and include minerals differing by the Ag + + Sb 3+ ↔ 2 Pb 2+ substitution percentage L% and by unit-cell parameter (Moëlo et al 1989;Makovicky and Topa 2014).…”

“…The Bi-Sb substitution is expressed in terms of Bi/(Bi + Sb) atomic ratio multiplied by 100, an ideal gustavite with no Sb being 4 Gus (Makovicky and Topa 2014). Natural antimonian lillianite homologues are known only for N = 4 ( 4,4 L) and include minerals differing by the Ag + + Sb 3+ ↔ 2 Pb 2+ substitution percentage L% and by unit-cell parameter (Moëlo et al 1989;Makovicky and Topa 2014). Andorite VI is defined as a phase with substitution percentage L% = 100, formula AgPbSb 3 S 6 (And 100 ) and the c parameter six times that of the subcell c = 6c' (c' ≈ 4 Å, subcell parameter).…”

“…Ramdohrite (Cd,Mn,Fe) (And 136.5 ). The oversubstitution takes place by replacing of Pb atom in trigonal prismatic coordination (Makovicky and Topa 2014).…”

Mineralogy of the Silver King deposit, Omeo, Victoria

“…The name applies to a discrete phase on a series line in the Ag-Sb-Pb(-S) system, where the historic 'grandfathered' names andorite IV and andorite VI represent limits of a very small substitution range (Makovicky & Topa 2014 (Figure 10). It is possible that Stillwell observed andorite but misidentified it as tetrahedrite.…”