What is Zinkenite?
Zinkenite is a soft lead-antimony sulfosalt with a metallic grey colour and fibrous or acicular habit, a classic specimen for collectors of complex hydrothermal ore minerals.
Mineralogy and structure
Reference formula: Pb9Sb22S42. Zinkenite is hexagonal with the ideal formula Pb9Sb22S42. Natural sulfosalts can show homologous-series substitutions, so analysis and locality are important; the Guide model is a labelled representative COD structure. Zinkenite is classified with sulfosalts and has hexagonal crystal symmetry. Typical hardness is 2.5–3 on the Mohs scale and specific gravity is approximately 5.3–5.5.
Colour, lustre and habit
Typical colours include lead grey, black, steel grey. The usual acicular, fibrous, massive habit and metallic, sub-metallic lustre help describe a specimen, but colour alone is not diagnostic.
Formation and notable localities
Zinkenite forms in or is associated with low- to medium-temperature hydrothermal lead-antimony veins and replacement deposits. Important documented localities include Bolivia, Romania, Germany, Italy, Mexico and other antimony-rich ore districts.
Metallic needles from a historic ore vein
Zinkenite is visually compelling because its fine metallic fibres look almost textile-like. A documented specimen turns that texture into a serious story about lead-antimony ore formation.
Collecting and care
Lead- and antimony-bearing: keep enclosed, avoid dust, grinding and acids, and wash hands after handling. Protect the soft fibrous surfaces from scratches.
