Re-examination of fluosiderite, an unknown mineral from southern Italy; equal to fluorine-rich chondrodite

Chemical and X-ray diffraction analyses allowed re-identification of the Scacchi’s fluosiderite from Fiano (old quarry NE of Naples) as a fluorine- rich chondrodite, general formula: M(2n-1) Si(n)O(2n).2M(OH,F)O. The genesis of this particular mineral assemblage is related to the emplacement of hot and volatile (mainly fluorine)-rich pyroclastic flow of the Campanian Ignimbrite.