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Hydroxylbenyacarite, (H2O)2Mn2(Ti2Fe)(PO4)4[O(OH)](H2O)10⋅4H2O, a new paulkerrite-group mineral, from the El Criollo mine, Cordoba Province, Argentina.
- Rupert Hochleitner, Christian Rewitzer, Ian E. Grey, Anthony R. Kampf, Colin M. MacRae, Robert W. Gable, William G. Mumme
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- Journal:
- Mineralogical Magazine , FirstView
- Published online by Cambridge University Press:
- 19 March 2024, pp. 1-8
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Hydroxylbenyacarite, (H2O)2Mn2(Ti2Fe)(PO4)4[O(OH)](H2O)10⋅4H2O, is a new paulkerrite-group mineral from the El Criollo mine, Cordoba Province, Argentina (IMA2023–079). It was found in specimens of altered triplite, in association with bermanite, phosphosiderite, quartz, strengite and manganese oxides.
Hydroxylbenyacarite occurs as light greenish-yellow rhombic tablets with dimensions of typically 20 to 50 μm, occasionally to 400 μm. The crystals are flattened on {010}, slightly elongated on [001] and bounded by the {111} and {010} forms. The calculated density is 2.32 g cm–3. Optically, hydroxylbenyacarite crystals are biaxial (+), with α = 1.608(3), β = 1.624(3), γ = 1.642(3) (measured in white light) and 2V(meas.) = 88(2)°. The calculated 2V is 87.5°. The empirical formula is Ca0.06 A[K0.46(H2O)0.88□0.66]Σ2.00 M1(Mn1.52Mg0.02Fe2+0.35□0.11)Σ2.00 M2+M3(Fe3+1.21Al0.02Ti1.77)Σ3.00(PO4)4 X[F0.16(OH)0.70O1.14]Σ2.00(H2O)10⋅3.77H2O.
The average crystal structure for hydroxylbenyacarite has space group Pbca and unit cell parameters a = 10.5500(3) Å, b =20.7248(5) Å, c = 12.5023(3) Å, V = 2733.58(12) Å3 and Z = 4. It was refined using single-crystal data to wRobs = 0.074 for 2611 reflections with I > 3σ(I). The crystal structure contains corner-connected linear trimers of Ti-centred octahedra that share corners with PO4 tetrahedra to form 10-member rings parallel to (010). K+ cations and water molecules are located in interstitial sites within the rings. Additional corner-sharing of the PO4 tetrahedra with MnO2(H2O)4 octahedra occurs along [010] to complete the 3D framework structure. A new eight-coordinated interstitial site, previously unreported for paulkerrite-group minerals, is occupied by Ca2+ cations. Weak diffuse diffraction spots in reconstructed precession images for hydroxylbenyacarite violate the a and b glide plane extinctions for Pbca and are consistent with local, unit-cell-scale regions of monoclinic, P21/c structure, in which ordering of the interstitial K+ and Ca2+ cations occurs.
Whiteite-(MnMnMn), a new jahnsite-group mineral species from the Foote mine, North Carolina, USA, and chemical pressure effects in jahnsite-group minerals.
- Ian E. Grey, Jason B. Smith, Anthony R. Kampf, W. Gus Mumme, Colin M. MacRae, Alan Riboldi-Tunnicliffe, Stephanie Boer, Alexander M. Glenn, Robert W. Gable
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- Journal:
- Mineralogical Magazine / Volume 85 / Issue 6 / December 2021
- Published online by Cambridge University Press:
- 18 October 2021, pp. 862-867
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Whiteite-(MnMnMn), Mn2+Mn2+Mn2+2Al2(PO4)4(OH)2⋅8H2O, is a new whiteite-subgroup member of the jahnsite group from the Foote Lithium Company mine, Kings Mountain district, Cleveland County, North Carolina, USA. It was found in small vugs of partially oxidised pegmatite minerals on the East dump of the mine, in association with eosphorite, hureaulite, fairfieldite, mangangordonite, whiteite-(CaMnMn) and jasonsmithite. It occurs as sugary aggregates of blade-like crystals up to 0.1 mm long and as epitaxial overgrowths on whiteite-(CaMnMn). The crystals are colourless to very pale brown, with a vitreous lustre and a white streak. The blades are flattened on {001} and elongated along [010], with poor cleavage on {001}. The calculated density is 2.82 g⋅cm–3. Optically it is biaxial (–) with α = 1.599(2), β = 1.605(2), γ = 1.609(2) (white light); 2V (calc.) = 78.2°, having no observable dispersion or pleochroism, and with orientation X = b. Electron microprobe analyses and structure refinement gave the empirical formula (Mn2+0.59Ca0.38Na0.03)Σ1.00Mn1.00(Mn2+1.04Fe3+0.58Fe2+0.23Zn0.16Mg0.08)Σ2.09Al2.04(PO4)3.89(OH)3.18(H2O)7.26. Whiteite-(MnMnMn) is monoclinic, P2/a, a = 15.024(3) Å, b = 6.9470(14) Å, c = 9.999(2) Å, β = 110.71(3)°, V = 976.2(4) Å3 and Z = 2. The crystal structure was refined using synchrotron single-crystal data to wRobs = 0.057 for 2014 reflections with I > 3σ(I). Site occupancy refinements confirm the ordering of dominant Mn in the X, M1 and M2 sites of the general jahnsite-group formula XM1(M2)2(M3)2(H2O)8(OH)2(PO4)4. A review of published crystallochemical data for jahnsite-group minerals shows a consistent chemical pressure effect in these minerals, manifested as a contraction of the unit-cell parameter, a, as the mean size of the X and M1 site cations increases. This is analogous to negative thermal expansion, but with increasing cation size, rather than heating, inducing octahedral rotations that result in an anisotropic contraction of the unit cell.
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- By Zachary W. Adams, Margarita Alegría, Atalay Alem, Jordi Alonso, Victor Aparicio, Rifat Atun, Florence Baingana, Emily Baron, Marco Bertelli, Dinesh Bhugra, Sanchita Biswas, José Miguel Caldas de Almeida, Edwin Cameron, Somnath Chatterji, Erminia Colucci, Janice L. Cooper, Carla Kmett Danielson, Diego De Leo, Mary-Jo DelVecchio Good, Marten W. de Vries, Maureen S. Durkin, Xiangming Fang, Julia W. Felton, Sally Field, Andrea Fiorillo, Lance Gable, Teddy Gafna, Sandro Galea, Patrick Gatonga, Sofia Halperin-Goldstein, Yanling He, Grace A. Herbert, Sabrina Hermosilla, Simone Honikman, Takashi Izutsu, Ruwan M. Jayatunge, Janis H. Jenkins, Rachel Jenkins, Lynne Jones, Jayanthi Karunaratne, Ronald C. Kessler, Rob Keukens, Lincoln I. Khasakhala, Hanna Kienzler, Sarah Kippen Wood, M. Thomas Kishore, Robert Kohn, Natasja Koitzsch Jensen, Sheri Lapatin, Anna Lessios, Isabel Louro Bernal, Feijun Luo, Laura MacPherson, Matthew J. Maenner, Anne W. Mbwayo, David McDaid, Ingrid Meintjes, Victoria N. Mutiso, David M. Ndetei, Samuel O. Okpaku, Lijing Ouyang, Ramachandran Padmavati, Clare Pain, Duncan Pedersen, Jordan Pfau, Felipe Picon, Rodney D. Presley, Reima Pryor, Shoba Raja, Thara Rangaswamy, Jorge Rodriguez, Diana Rose, Moosa Salie, Norman Sartorius, Ester Shapiro, Manuela Silva, Daya Somasundaram, Katherine Sorsdahl, Dan J. Stein, Deborah M. Stone, Heather Stuart, Athula Sumathipala, Hema Tharoor, Rita Thom, Lay San Too, Atsuro Tsutsumi, Chris Underhill, Anne Valentine, Claire van der Westhuizen, Thandi van Heyningen, Robert van Voren, Inka Weissbecker, Gail Wyatt
- Edited by Samuel O. Okpaku
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- Book:
- Essentials of Global Mental Health
- Published online:
- 05 March 2014
- Print publication:
- 27 February 2014, pp x-xiv
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