What is Xilingolite?
Xilingolite is a lead-bismuth sulfide of the lillianite homologous series, valued for metallic lustre and its place in complex hydrothermal ore assemblages.
Mineralogy and structure
Reference formula: Pb3Bi2S6. Xilingolite is monoclinic with the idealised formula Pb3Bi2S6 and is related to lillianite. COD 9004662 is used as an exact structural reference; homologous-series chemistry can vary. Xilingolite is classified with sulfides and has monoclinic crystal symmetry. Typical hardness is 3–3.5 on the Mohs scale and specific gravity is approximately 6.8–7.2.
Colour, lustre and habit
Typical colours include lead grey, grey, black. The usual prismatic, granular, massive habit and metallic, sub-metallic lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Xilingolite forms in or is associated with hydrothermal lead-bismuth veins, metamorphosed ore deposits and sulfide-rich skarns. Important documented localities include the Chaobuleng deposit in Inner Mongolia, Austria, Michigan, China and other lead-bismuth districts.
Metallic grey geometry in the lillianite series
Xilingolite appeals to ore-mineral collectors because a small metallic fragment can show the structural logic of a whole homologous series. Locality and analysis are essential.
Collecting and care
Lead- and bismuth-bearing: keep enclosed, avoid dust, grinding and acids, and wash hands after handling.
