Chukhrovite-(Ca): una nuova specie mineralogica dalla miniera di Val Cavallizza, Cuasso al Monte (VA)

Chukhrovite-(Ca), Ca4.5Al2(SO4)F13 ?12H2O, is the Ca-dominant species of the chukhrovite mineral group. It occurs at the Val Cavallizza Pb- Zn-Ag mine, Cuasso al Monte, Varese province as low temperature hydrothermal crystallizations covering the surfaces of brittle fractures crosscutting a marcasite and REE-bearing fluorite vein. Associated minerals include anglesite, barite, fluorite, galena, gypsum, jarosite, marcasite, sphalerite and sulphur. This new calcium aluminofluoride forms transparent to translucent, colorless to whitish sharp octahedra up to 150 ?m in diameter. Its unit-cell parameter is: a = 16.749(1) Å.