MINERALOGICAL MAGAZINE JOURNAL OF THE MINERALOGICAL SOCIETY

Summary. Onoratoite, a new ant imony oxyehloride Sbs011C12 from the antimony mines of Cetine di Cotorniano, Rosia (Siena, Italy), is trielinic with lattice con-stants a 18.92, b 4.03, c 10-31 ~, a ~ ~-- 90 ~ fl 110 ~ Density 5.3 meas., 5.49 cale. The needle-like crystals are elongated on [010] and show as prominent form {001}. Other forms present are {100}, {201}, {401}, {412}. The new mineral is optically biaxial negative, extinction angle small and variable from 0 ~ to 14 ~ Orientation]3:[100] ca. 8 ~ a:[001] ca. 12 ~?:[010] 0 to 14 ~ Re