Stibioclaudetite ASSB0₃ a new mineral from tsumeb, namibia

Stibioclaudetite is a new mineral species with ideal chemistry AsSb0 ₃. The mineral has monoclinic symmetry, P2¹/n, with a = 4.5757(4)Å,b = 13.1288(13) A, c = 5.4216(5) Å, ß = 95.039(4)°, V = 324.44(5) ^Å3, Z = 4, and d_caic = 5.009 g/cm³. The strongest X-ray lines (calculated) are 3.512 (100), 3.282 (82), 3.238 (71), 2.279 (34), and 4.995 (32). The average of ten microprobe analyses is 45.15% As₂0₃ and 55.77% Sb ₂0₃, total 100.92, corresponding to As _1.088Sb_0.912O₃. Stibioclaudetite forms adamantine, colorless transparent bladed crystals to 6 mm, bound by {010}, {110}, {111}, and {101}. The mineral is flexible with perfect cleavage on {010}. The hardness is <2; indices of refraction are >2.00. Stibioclaudetite occurs with leiteite, ludlockite, smithsonite and quartz in a vug within massive tennantite from the Tsumeb mine, Tsumeb, Namibia. Stibioclaudetite is isostructural with claudetite, specifically an Sb-substituted ordered analog, and the name denotes the relationship. The crystal structure consists of corrugated sheets of corner-sharing As0₃ and Sb0₃ trigonal pyramids arranged in an ordered, alternating pattern. Raman spectra of stibioclaudetite, claudetite, and leiteite are presented and compared.