Pohlite, a new lead iodate hydroxide chloride from Sierra Gorda, Chile

Abstract

The new mineral pohlite (IMA2022-043), Pb7(IO3)(OH)4Cl9, was found at the La Compania mine, Sierra Gorda, Antofagasta Province, Antofagasta, Chile, where it occurs in cavities in an oxidized portion of a quartz vein in association with massive aragonite and anhydrite. Pohlite crystals are transparent, colourless to pale gray, blades, up to 4 mm in length. The mineral has white streak, adamantine lustre and is nonfluorescent. It is brittle with irregular, conchoidal fracture. The Mohs hardness is ~2½ and it has no cleavage. The calculated density is 5.838(2) g cm -3 . Optically, the mineral is biaxial (+) with α < 2.01(est.), β = 2.02 (calc.), γ = 2.05 (calc.); 2V = 60(5)°; moderate r > v dispersion; orientation: Y ^ a ≈