Whiteite-(CaMnFe), a new jahnsite-group mineral from the Hagendorf-Sudpegmatite, Oberpfalz, Bavaria

Whiteite-(CaMnFe), CaMn2+Fe22+Al2(PO4)(4)(OH)(2) . 8H(2)O, is a new whiteite-subgroup member of the jahnsite group from the Hagendorf-Sud pegmatite, Oberpfalz, Bavaria, Germany. It was found in vugs in an altered feldspar area of a specimen composed predominantly of rockbridgeite, with hureaulite and relic triphylite. Other associated minerals in small vugs in the specimen were strengite and laueite. Whiteite-(CaMnFe) occurs as sprays and clusters of colourless to pale yellow, rod-like crystals, with diameters of typically 10 to 50 mu m and lengths up to & SIM; 500 mu m. The crystals are flattened on {001} and elongated along [010]. The measured density is 2.80(2) g cm(-3). Optically, whiteite-(CaMnFe) crystals are biaxial (+), with alpha=1.608(3), beta=1.612(3), gamma=1.624(3) and 2V(meas.) = 59(1)?degrees. The empirical formula from electron microprobe analyses and structure refinement is (Ca0.70Mn0.30)Mn(Fe1.232+Mn0.49Mg0.29Zn0.06)(Al1.88Fe0.123+)(PO4)(3.96)(OH)(2)(H2O)(8). Whiteite-(CaMnFe) is monoclinic, P2 /a, a=14.925(5), b=7.0100(14), c=10.053(2) angstrom, beta=111.31(2)?degrees, V=979.9(4) angstrom(3) and Z=2. The crystal structure was refined using single-crystal data to wR(obs)=0.052 for 1613 reflections with I > 3 sigma(I). Site occupancy refinements confirm the ordering of dominant Ca, Mn and Fe2+ in the X, M1 and M2 sites, respectively, of the general jahnsite-group formula XM1M2(2)M3(2)(H2O)(8)(OH)(2)(PO4)(4).

Automated summary

Whiteite-(CaMnFe) is a new whiteite-subgroup member of the jahnsite group discovered in the Hagendorf-Sud pegmatite in Bavaria, Germany. It occurs as colorless to pale yellow rod-like crystals and has a monoclinic crystal structure.