Etzenricht, Germany
Etzenricht, Germany

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Mills S.J.,Khan Research Laboratories | Grey I.E.,CSIRO | Kampf A.R.,Natural History Museum of Los Angeles County | Birch W.D.,Khan Research Laboratories | And 3 more authors.
European Journal of Mineralogy | Year: 2016

Kayrobertsonite, MnAl2(PO4)2(OH)2 6H2O, is a new secondary phosphate mineral from the Hagendorf Süd pegmatite, Hagendorf, Oberpfalz, Bavaria, Germany and the Foote Lithium Company mine, Kings Mountain district, Cleveland County, North Carolina, USA. Kayrobertsonite crystals occur as intergrown masses of snow-white, soft, finely fibrous needles, less than 5 mm in diameter and no more than 100 mm in length. Quantitative analysis of Foote mine kayrobertsonite gave the empirical formula: Mn0.97Ca0.03Fe0.02Al1.87(PO4)2(OH)1.62F0.03(H2O)0.38 6H2O; and for Hagendorf Süd kayrobertsonite: Mn0.92Ca0.06Fe0.02Al1.87(PO4)2 (OH)1.19F0.42(H2O)0.39 6H2O. Foote mine kayrobertsonite crystals are biaxial (-), with indices of refraction a = 1.530(1), b = 1.554(1), g = 1.566(1), measured in white light; 2V(meas.) is 70.3(5)-, while 2V(calc.) is 69.6°. The mineral is nonpleochroic. The orientation of the crystals is Z ≈ c (length slow). Kayrobertsonite is triclinic, space group P1, with the unit-cell parameters: A = 10.049(2), b = 10.205(2), c = 6.083(1)A ° , a = 91.79(3), b = 99.70(3), g = 98.02(3)°, V = 607.9(2)A ° 3 and Z = 2 (Foote mine). The polyhedral framework in kayrobertsonite has the same topology as that in nordgauite, but with replacement of F by OH at the bridging anion sites. The main crystal chemical change from nordgauite to kayrobertsonite is a doubling of the number of water molecules in the [001] channels. © 2016 E. Schweizerbart'sche Verlagsbuchhandlung.

Grey I.E.,CSIRO | MacRae C.M.,CSIRO | Keck E.,Algunderweg 3 | Birch W.D.,Khan Research Laboratories
Mineralogical Magazine | Year: 2012

Aluminium-bearing strunzite, [Mn0.65Fe0.26Zn 0.08Mg0.01]2+[Fe1.50Al 0.50]3+(PO4)2(OH) 2•6H2 O, occurs as fibrous aggregates in a crystallographically oriented association with jahnsite on altered zwieselite samples from the phosphate pegmatite at Hagendorf Süd, Bavaria, Germany. Synchrotron X-ray data were collected from a 3 μm diameter fibre and refined in space group P1 to R 1 = 0.054 for 1484 observed reflections. The refinement confirmed the results of chemical analyses which showed that one quarter of the trivalent iron in the strunzite crystals is replaced by aluminium. The paragenesis revealed by scanning electron microscopy, in combination with chemical analyses and a crystal-chemical comparison of the strunzite and jahnsite structures, are consistent with strunzite being formed from jahnsite by selective leaching of (100) metal phosphate layers containing large divalent Ca and Mn atoms. © 2012 Mineralogical Society.

Grey I.E.,CSIRO | Keck E.,Algunderweg 3 | Mumme W.G.,CSIRO | Macrae C.M.,CSIRO | And 3 more authors.
Mineralogical Magazine | Year: 2015

Crystals of laueite, Mn2+Fe3+ 2(PO4)2(OH)2·8H2O, from the Cornelia mine open cut, Hagendorf Süd, Bavaria, are zoned due to aluminium incorporation at the iron sites, with analysed Al2O3 contents varying up to 11 wt.%. Synchrotron X-ray data were collected on two crystals with different Al contents and the structures refined. The laueite structure contains two independent Fe3+-containing sites; M2 and M3, which alternate in 7 Å corner-connected octahedral chains. The coordination polyhedra are different for the two sites, M2O4(OH)2 and M3O2(OH)2(H2O)2 respectively. The structure refinements show that Al preferentially orders into site M3. Refined site occupancies for M2 and M3 for the two crystals are: for crystal L-1, M2 = 0.70(1) Fe + 0.30(1) Al, M3 = 0.54(1) Fe + 0.46(1) Al and for crystal L-2, M2 = 0.67(1) Fe + 0.33(1) Al, M3 = 0.48(1) Fe + 0.52(1) Al. For crystal L-2, the octahedral chains have dominant Fe in M2, alternating with dominant Al in M3 along the chain, an ordering phenomenon not previously reported for laueite-related minerals. © 2015 Mineralogical Society 2015.

Grey I.E.,CSIRO | Keck E.,Algunderweg 3 | Mumme W.G.,CSIRO | Pring A.,South Australian Museum | And 3 more authors.
Mineralogical Magazine | Year: 2015

Flurlite, ideally Zn3Mn2+Fe3+(PO4)3(OH)2·9H2O, is a new mineral from the Hagendorf-Süd pegmatite, Hagendorf, Oberpfalz, Bavaria, Germany. Flurlite occurs as ultrathin (<1 μm) translucent platelets that form characteristic twisted accordion-like aggregates. The colour varies from bright orange red to dark maroon red. Cleavage is perfect parallel to (001). The mineral occurs on mitridatite and is closely associated with plimerite. Other associated minerals are beraunite, schoonerite, parascholzite, robertsite and altered phosphophyllite. The calculated density of flurlite is 2.84 g cm-3. It is optically biaxial (-), α = 1.60(1), β = 1.65(1) and γ = 1.68(1), with weak dispersion and parallel extinction, X ≈c, Y ≈ a, Z ≈ b. Pleochroism is weak, with colours: X = pale yellow, Y = pale orange, Z = orange brown. Electron microprobe analyses (average of seven) with FeO and Fe2O3 apportioned and H2O calculated on structural grounds, gave ZnO 25.4, MnO 5.28, MgO 0.52, FeO 7.40, Fe2O3 10.3, P2O5 27.2, H2O 23.1, total 99.2 wt.%. The empirical formula, based on 3 P a.p.f.u. is Zn2.5Mn2+ 0.6Fe2+ 0.8Mg0.1Fe3+(PO4)3(OH)2·9H2O. Flurlite is monoclinic, P21/m, with the unit-cell parameters (at 100 K) of a = 6.3710(13), b = 11.020(2), c = 13.016(3) Å, β = 99.34 (3)°. The strongest lines in the X-ray powder diffraction pattern are [dobs in Å(I) (hkl)] 12.900(100)(001); 8.375(10)(011); 6.072(14)( 101); 5.567(8)(012); 4.297(21)(003); 2.763(35)(040). Flurlite (R1 = 0.057 for 995 F > 4σ(F)) has a heteropolyhedral layer structure, with layers parallel to (001) and with water molecules packing between the layers. The slab-like layers contain two types of polyhedral chains running parallel to [100]: (a) chains of edge-sharing octahedra containing predominantly Zn and (b) chains in which Fe3+-centred octahedra share their apices with dimers comprising Zn-centred trigonal bipyramids sharing an edge with PO4 tetrahedra. The two types of chains are interconnected by corner-sharing along [010]. A second type of PO4 tetrahedron connects the chains to MnO2(H2O)4 octahedra along [010] to complete the structure of the (001) slabs. Flurlite has the same stoichiometry as schoonerite, but with dominant Zn rather than Fe2+ in the edge-shared chains. Schoonerite has a similar heteropolyhedral layer structure with the same layer dimensions 6.4 × 11.1 Å. The different symmetry (orthorhombic, Pmab) for schoonerite reflects a different topology of the layers. © 2015 by Walter de Gruyter Berlin/Boston.

Birch W.D.,Khan Research Laboratories | Grey I.E.,CSIRO | Mills S.J.,Natural History Museum of Los Angeles County | Pring A.,South Australian Museum | And 4 more authors.
Mineralogical Magazine | Year: 2011

Nordgauite, MnAl 2(PO 4) 2(F,OH) 2•5H 2O, is a new secondary phosphate from the Hagendorf-Süd pegmatite, Bavaria, Germany. It occurs as white to off-white compact waxy nodules and soft fibrous aggregates a few millimetres across in altered zwieselite-triplite. Individual crystals are tabular prismatic, up to 200 μm long and 10 μm wide. Associated minerals include fluorapatite, sphalerite, uraninite, a columbite-tantalite phase, metastrengite, several unnamed members of the whiteite-jahnsite family, and a new analogue of kingsmountite. The fine-grained nature of nordgauite meant that only limited physical and optical properties could be obtained; streak is white; fracture, cleavage and twinning cannot be discerned. D meas. and D calc. are 2.35 and 2.46 g cm -3, respectively; the average RI is n = 1.57; the Gladstone-Dale compatibility is - 0.050 (good). Electron microprobe analysis gives (wt.%): CaO 0.96, MgO 0.12, MnO 14.29, FeO 0.60, ZnO 0.24, Al 2O 3 22.84, P 2O 5 31.62, F 5.13 and H 2O 22.86 (by CHN), less F=O 2.16, total 96.50. The corresponding empirical formula is (Mn 0.90Ca 0.08Fe 0.04Zn 0.01Mg 0.01) Σ1.04Al2.01(PO 4) 2[F 1.21,(OH) 0.90] Σ2.11•5.25H 2O. Nordgauite is triclinic, space group P1̄, with the unit-cell parameters: a = 9.920(4), b = 9.933(3), c = 6.087(2) Å, α = 92.19(3), β = 100.04(3), γ = 97.61(3)°, V = 584.2(9) Å 3 and Z = 2. The strongest lines in the XRD powder pattern are [d in Å (I) (hkl)] 9.806 (100)(010), 7.432 (40)(110), 4.119 (20)(210), 2.951 (16)(03̄1), 4.596 (12)(21̄0), 3.225 (12)(220) and 3.215 (12)(121). The structure of nordgauite was solved using synchrotron XRD data collected on a 60 μm × 3 μm × 4 μm needle and refined to R 1 = 0.0427 for 2374 observed reflections with F > 4σ(F). Although nordgauite shows stoichiometric similarities to mangangordonite and kastningite, its structure is more closely related to those of vauxite and montgomeryite in containing zig-zag strings of corner-connected Al-centred octahedra along [011], where the shared corners are alternately in cis and trans configuration. These chains link through corner-sharing with PO 4 tetrahedra along [001] to form (100) slabs that are interconnected via edge-shared dimers of MnO 6 polyhedra and other PO 4 tetrahedra. © 2011 Mineralogical Society.

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