Eur. J. Mineral., 32, 449–455, 2020 https://doi.org/10.5194/ejm-32-449-2020 © Author(s) 2020. This work is distributed under the Creative Commons Attribution 4.0 License. Luxembourgite, AgCuPbBi4Se8, a new mineral species from Bivels, Grand Duchy of Luxembourg Simon Philippo1, Frédéric Hatert2, Yannick Bruni2, Pietro Vignola3, and Jiríˇ Sejkora4 1Laboratoire de Minéralogie, Musée National d’Histoire Naturelle, Rue Münster 25, 2160 Luxembourg, Luxembourg 2Laboratoire de Minéralogie, Université de Liège B18, 4000 Liège, Belgium 3CNR-Istituto di Geologia Ambientale e Geoingegneria, via Mario Bianco 9, 20131 Milan, Italy 4Department of Mineralogy and Petrology, National Museum, Cirkusová 1740, 193 00 9, Prague, Czech Republic Correspondence: Frédéric Hatert (
[email protected]) Received: 24 March 2020 – Revised: 30 June 2020 – Accepted: 15 July 2020 – Published: 12 August 2020 Abstract. Luxembourgite, ideally AgCuPbBi4Se8, is a new selenide discovered at Bivels, Grand Duchy of Lux- embourg. The mineral forms tiny fibres reaching 200 µm in length and 5 µm in diameter, which are deposited on dolomite crystals. Luxembourgite is grey, with a metallic lustre and without cleavage planes; its Mohs hard- ness is 3 and its calculated density is 8.00 g cm−3. Electron-microprobe analyses indicate an empirical formula Ag1:00.Cu0:82Ag0:20Fe0:01/61:03Pb1:13Bi4:11.Se7:72S0:01/67:73, calculated on the basis of 15 atoms per formula unit. A single-crystal structure refinement was performed to R1 D 0:0476, in the P 21=m space group, with 3 a D 13:002.1/, b D 4:1543.3/, c D 15:312.2/Å, β D 108:92.1/◦, V D 782:4.2/Å , Z D 2.