Baliczunicite, Bi_2O(SO_4)_2, a new fumarole mineral from La Fossa crater, Vulcano, Aeolian Islands, Italy

摘要

Baliczunicite, ideally Bi_2O(SO_4)_2, is a new mineral found as a high-temperature fumarole sublimate (T = 600°C) at La Fossa crater, Vulcano, Aeolian Islands, Italy. It occurs as aggregates of |im-sized prismatic and elongated crystals (-50 μm across and up to 200 urn long) associated with anglesite, leguernite, one other potentially new Bi-oxysulfate mineral, lillianite, galenobismutite, bismoclite, Cd-rich sphalerite, wurtzite, pyrite and pyrrhotite. Baliczunicite is colourless to white or pale brown, transparent and non-fluorescent. It has a vitreous lustre and a white streak. Electron microprobe analysis gives the following average chemical composition (wt.%): Bi_2O_3 68.68 and SO_3 23.73, total 92.41. The empirical chemical formula, calculated on the basis of 9 anions p.f.u., is Bi_(1.99)S_2O_9. The calculated density is 5.911 g/cm~3.Baliczunicite is triclinic, space group PI, with a 6.7386(3), b 11.1844(5), c 14.1754(7) A, a 80.082(2)°, |3 88.462(2)°, y 89.517(2)°, V= 1052.01(8) A3 and Z = 6. The six strongest reflections in the X-ray powder-diffraction data [d in A (I) (hkl)] are: 3.146 (100) (033), 3.486 (21) (004), 3.409 (12) (031), 3.366 (7) (200), 5.562 (4) (111), 5.433 (4) (111). Baliczunicite is the natural analogue of the stable low-temperature a form of synthetic Bi_2O(SO_4)_2. The name is in honour of Tonci Balic-Zunic (born 1952), Professor of Mineralogy at the Natural History Museum of the University of Cophenagen. Both the mineral and the mineral name have been approved by the IMA-CNMNC Commission (IMA2012-098).