Stunning Cacoxenite Crystals From Spain Minerals 7:39 PM A+ A- Print Email Photo: Honorio Cocera-La Parra Cacoxenite Formula: Fe3+24Al(PO4)17O6(OH) 12· 17(H2O) System: HexagonalColour: Yellow to brownish ...Hardness: 3 – 4 From: Benetusser, Valencia, Spain It was first described in 1825 for an occurrence in the Hrbek Mine, Bohemia, Czech Republic. It occurs as a secondary phase in oxidized magnetite and limonite deposits. It also occurs in novaculites and in iron and phosphorus rich sediments.