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  • 1.
    Altieri, Alessandra
    et al.
    Sapienza University, Rome, Italy.
    Luppi, Riccardo
    Sapienza University, Rome, Italy.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Tempesta, Gioacchino
    Università degli Studi di Bari Aldo Moro, Bari, Italy.
    Pezzotta, Federico
    MUM–Mineralogical Museum “Luigi Celleri”,Campo nell’Elba, Leghorn, Italy.
    Bosi, Ferdinando
    Sapienza University, Rome, Italy.
    Thermal treatment of the tourmaline Fe-rich princivalleite Na(Mn2Al)Al6(Si6O18)(BO3)3(OH)3O2023In: Physics and chemistry of minerals, ISSN 0342-1791, E-ISSN 1432-2021, Vol. 50, no 4, p. 1-12, article id 27Article in journal (Refereed)
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  • 2. Altieri, Alessandra
    et al.
    Pezzotta, Federico
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Bosi, Ferdinando
    Blue growth zones caused by Fe2+ in tourmaline crystals from the San Piero in Campo gem-bearing pegmatites, Elba Island, Italy2022In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 86, no 6, p. 910-919Article in journal (Refereed)
  • 3. Altieri, Alessandra
    et al.
    Pezzotta, Federico
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Bosi, Ferdinando
    Dark-coloured Mn-rich overgrowths in an elbaitic tourmaline crystal from the Rosina pegmatite, San Piero in Campo, Elba Island, Italy: witness of late-stage opening of the geochemical system2023In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 87, no 1, p. 130-142Article in journal (Refereed)
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  • 4.
    Andreozzi, Giovanni
    et al.
    Sapienza Università di Roma, Italy.
    D'Ippolito, Veronica
    Sapienza Università di Roma, Italy.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Bosi, Ferdinando
    Sapienza Università di Roma, Italy.
    Color mechanisms in spinel: a multi-analytical investigation of natural crystals with a wide range of coloration.2019In: Physics and chemistry of minerals, ISSN 0342-1791, E-ISSN 1432-2021, Vol. 46, no 4, p. 343-360Article in journal (Refereed)
  • 5.
    Ardit, Matteo
    et al.
    University of Ferrara, Italy.
    Cámara, Fernando
    University of Milano, Italy.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Vanadium-induced coloration in grossite (CaAl4O7) and hibonite (CaAl12O19)2021In: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 106, no 4, p. 599-608Article in journal (Refereed)
    Abstract [en]

    High concentrations of vanadium cause very unusual coloration in hibonite (purple) and grossite (light violet) crystals in an exotic mineral assemblage from Sierra de Comechingones (Argentina). In the hibonite (CaAl12O19) structure vanadium ions, in various valence states (divalent, trivalent, and tetravalent), may be distributed over five crystallographic sites with coordinations corresponding to different polyhedra, namely, three unequal octahedra [M1 (D3d), M4 (C3ν), and M5 (Cs)], one M3 tetrahedron (C3ν), and one unusual fivefold-coordinated trigonal bipyramid M2 (D3h). Possible locations of vanadium ions in grossite (CaAl4O7) are limited to two crystallographically distinct sites (T1 and T2, both C1) in tetrahedral coordination.

    The combination of single-crystal X-ray diffraction and absorption spectroscopy techniques aided by chemical analyses has yielded details on the nature of the vanadium-induced color in both hibonite and grossite crystals. In hibonite, both M4 face-sharing octahedral and M2 trigonal bipyramid sites of the R-block are partially occupied by V3+. Strongly polarized bands recorded at relatively low energies in optical absorption spectra indicate that V2+ is located at the M4 octahedral site of the hibonite R-block. Chemical analyses coupled with an accurate determination of the electron densities at structural sites in hibonite suggest that the vanadium ions occupy about 10 and 5% of the M4 and M2 sites, respectively. For grossite, polarized optical absorption spectra reveal no indications of V2+; all observed absorption bands can be assigned to V3+ in tetrahedral coordination. Although not evident by the observed electron densities at the T sites of grossite (due to the low-V content), longer bond distances, and a higher degree of polyhedral distortion suggest that V3+ is located at the T2 site.

  • 6.
    Bergström, Jan
    et al.
    Swedish Museum of Natural History, Department of Paleobiology.
    Hou, Xian-Guang
    Yunnan University, Kunming.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Gut contents and feeding in the Cambrian arthropod Naraoia2007In: GFF, ISSN 1103-5897, E-ISSN 2000-0863, Vol. 129, p. 71-76Article in journal (Refereed)
  • 7.
    Biagion, Cristian
    et al.
    Università di Pisa, Italy.
    Bosi, Ferdinando
    Sapienza Università di Roma, Italy.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Pasero, Marco
    Università di Pisa, Italy.
    The crystal structure of turneaureite, Ca5(AsO4)3Cl, the arsenate analog of chlorapatite and its relationships with the arsenate apatites johnbaumite and svabite2017In: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 102, p. 1981-1986Article in journal (Refereed)
    Abstract [en]

    The crystal structure of turneaureite, ideally Ca5(AsO4)3Cl, was studied using a specimen from the Brattfors mine, Nordmark, Värmland, Sweden, by means of single-crystal X-ray diffraction data. The structure was refinedto R1 = 0.017 on the basis of 716 unique reflectios with Fo > 4σ(Fo) in the P63/m space group, with unit-cell parameters a = 9.9218(3), c = 6.8638(2) Å, V = 585.16(4) Å3. The chemical composition of the sample, determined by electron-microprobe analysis, is (in wt%; average of 10 spot analyses): SO3 0.22, P2O5 0.20, V2O5 0.01, As2O5 51.76, SiO2 0.06, CaO 41.39, MnO 1.89, SrO 0.12, BaO 0.52, PbO 0.10, Na2O 0.02, F 0.32, Cl 2.56, H2Ocalc 0.58, O(≡F+Cl) –0.71, total 99.04. On the basis of 13 anions per formula unit, the empirical formula corresponds to (Ca4.82Mn0.17Ba0.02Sr0.01)∑5.02 (As2.94P0.02S0.02Si0.01)∑2.99O12[Cl0.47(OH)0.42F0.11]∑1.00.Turneaureite is topologically similar to the other members of the apatite supergroup: columns of face-sharing M1 polyhedra running along c are connected through TO4 tetrahedra with channels hosting M2 cations and X anions. Owing to its particular chemical composition, the studied turneaureite can be considered as a ternary calcium arsenate apatite; consequently it has several partially filledanion sites within the anion columns. Polarized single-crystal FTIR spectra of the studied sample indicate stronger hydrogen bonding and less diverse short-range atom arrangements around (OH) groups in turneaureite as compared to the related minerals johnbaumite and svabite. An accurate knowledge of the atomic arrangement of this apatite-remediation mineral represents an improvement in our understanding of minerals able to sequester and stabilize heavy metals such as arsenic in polluted areas.

  • 8.
    Biagioni, Cristian
    et al.
    Università di Pisa, Italy.
    Bindi, Luca
    Università di Firenze, Italy.
    Mauro, Daniela
    Università di Pisa.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Crystal chemistry of sulfates from the Apuan Alps (Tuscany, Italy). V. Scordariite, K8(Fe3+0.67ο0.33)[Fe3+3O(SO4)6(H2O)3)]2(H2O)11 , a new metavoltine-related mineral2019In: Minerals, E-ISSN 2075-163X, Vol. 9, no 11, p. 1-14, article id 0702Article in journal (Refereed)
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  • 9.
    Biagioni, Cristian
    et al.
    Università di Pisa, Pisa, Italy.
    Bonaccorsi, Elena
    Università di Pisa, Pisa, Italy.
    Perchiazzi, Natale
    Università di Pisa, Pisa, Italy.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Zaccarini, Federica
    Univeristy of Leoben, Leoben, Austria.
    Derbylite and graeserite from the Monte Arsiccio mine, Apuan Alps,Tuscany, Italy: occurrence and crystal-chemistry2020In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 84, no 5, p. 766-777Article in journal (Refereed)
    Abstract [en]

    New occurrences of derbylite, Fex2+Fe3+4–2xTi4+3+xSb3+O13(OH), and graeserite, Fex2+Fe3+4–2xTi4+3+xAs3+O13(OH), have been identified in the Monte Arsiccio mine, Apuan Alps, Tuscany, Italy. Derbylite occurs as prismatic to acicular black crystals in carbonate veins. Iron and Ti are replaced by V (up to 0.29 atoms per formula unit, apfu) and minor Cr (up to 0.04 apfu). Mössbauer spectroscopy confirmed the occurrence of Fe2+ (up to 0.73 apfu), along with Fe3+. The Sb/(As+Sb) atomic ratio ranges between 0.73 and 0.82. Minor Ba and Pb (up to 0.04 apfu) substitute. Derbylite is monoclinic, space group P21/m, with unit-cell parameters a = 7.1690(3), b = 14.3515(7),c = 4.9867(2) Å, β = 104.820(3)° and V = 495.99(4) Å3. The crystal structure was refined to R1 = 0.0352 for 1955 reflections with Fo > 4σ(Fo). Graeserite occurs as prismatic to tabular black crystals, usually twinned, in carbonate veins or as porphyroblasts in schist. Graeserite in the first kind of assemblage is V rich (up to 0.66 apfu), and V poor in the second kind (0.03 apfu). Along with minor Cr (up to 0.06 apfu), this element replaces Fe and Ti. The occurrence of Fe2+ (up to 0.68 apfu) is confirmed by Mössbauer spectroscopy. Arsenic is dominant over Sb and detectable amounts of Ba and Pb have been measured (up to 0.27 apfu). Graeserite is monoclinic, space group C2/m, with unit-cell parameters for two samples: a = 5.0225(7), b = 14.3114(18), c = 7.1743(9) Å,β = 104.878(3)°, V = 498.39(11) Å3; and a = 5.0275(4), b = 14.2668(11), c = 7.1663(5) Å, β = 105.123(4)° and V = 496.21(7) Å3. The crystal structures were refined to R1 = 0.0399 and 0.0237 for 428 and 1081 reflections with Fo > 4σ(Fo), respectively. Derbylite and graeserite are homeotypic. They share the same tunnel structure, characterised by an octahedral framework and cuboctahedral cavities, hosting (As/Sb)O3 groups and (Ba/Pb) atoms.

  • 10.
    Biagioni, Cristian
    et al.
    Università di Pisa, Italy.
    Bosi, Ferdinando
    Sapienza Università di Roma, Italy.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Pasero, Marco
    Università di Pisa, Italy.
    The crystal structure of svabite, Ca5(AsO4)3F, an arsenate member of the apatite supergroup2016In: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 101, p. 1750-1755Article in journal (Refereed)
    Abstract [en]

    The crystal structure of svabite, ideally Ca5(AsO4)3F, was studied using a specimen from the Jakobsberg mine, Värmland, Sweden, by means of single-crystal X‑ray diffraction data. The structure was refined to R1 = 0.032 on the basis of 928 unique reflections with Fo > 4s(Fo) in the P63/m space group, with unit-cell parameters a = 9.7268(5), c = 6.9820(4) Å, V = 572.07(5) Å3. The chemical composition of the sample, determined by electron-microprobe analysis, is (in wt%, average of 10 spot analyses): SO3 0.49, P2O5 0.21, V2O5 0.04, As2O5 51.21, SiO2 0.19, CaO 39.31, MnO 0.48, SrO 0.03, PbO 5.19, Na2O 0.13, F 2.12, Cl 0.08, H2Ocalc 0.33, O (≡ F+Cl) –0.91, total 98.90. On the basis of 13 anions per formula unit, the empirical formula corresponds to (Ca4.66Pb0.16Mn0.04Na0.03)Σ4.89(As2.96S0.04Si0.02P0.02)Σ3.04O12[F0.74(OH)0.24Cl0.01]. Svabite is topologically similar to the other members of the apatite supergroup: columns of face-sharing M1 polyhedra running along c are connected through TO4 tetrahedra with channels hosting M2 cations and X anions. The crystal structure of synthetic Ca5(AsO4)3F was previously reported as triclinic. On the contrary, the present refinement of the crystal structure of svabite shows no deviations from the hexagonal symmetry. An accurate knowledge of the atomic arrangement of this apatite-remediation mineral represents an improvement in our understanding of minerals able to sequester and stabilize heavy metals such as arsenic in polluted areas.

  • 11.
    Biagioni, Cristian
    et al.
    Università di Pisa, Italy..
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Miyawaki, Ritsuro
    National Museum of Nature and Science, Tsukuba, Japan.
    Pasero, Marco
    Università di Pisa, Italy..
    Nuove specie mineralogiche Italiane2019In: Rivista Mineralogica Italiana, Vol. 43, no 4, p. 256-262Article in journal (Other (popular science, discussion, etc.))
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  • 12.
    Biagioni, Cristian
    et al.
    Università di Pisa, Italy..
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Pasero, Marco
    Università di Pisa, Italy..
    Nuovi minerali Italiana - La approvazioni 20172018In: Revista Mineralogica Italiana, ISSN 0391-9641, Vol. 42, no 3, p. 190-197Article in journal (Other (popular science, discussion, etc.))
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  • 13.
    Biagioni, Cristian
    et al.
    Università di Pisa, Italy..
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Pasero, Marco
    Università di Pisa, Italy..
    Karlsson, Andreas
    Swedish Museum of Natural History, Department of Geology.
    Bosi, Ferdinando
    Sapienza Università di Roma, Italy.
    Hydroxylhedyphane, Ca2Pb3(AsO4)3(OH), a new member of the apatite supergroup from Långban, Sweden2019In: European journal of mineralogy, ISSN 0935-1221, E-ISSN 1617-4011, Vol. 31, no 5-6, p. 1007-1014Article in journal (Refereed)
  • 14.
    Biagioni, Cristian
    et al.
    Università di Pisa, Italy..
    Pasero, Marco
    Università di Pisa, Italy..
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Bosi, Ferdinando
    Sapienza Università di Roma, Italy.
    Bianchiniite, Ba2(Ti4+V3+)(As2O5)2OF, a new diarsenite mineral fromthe Monte Arsiccio mine, Apuan Alps, Tuscany, Italy2021In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 3, p. 354-363Article in journal (Refereed)
    Abstract [en]

    The new mineral bianchiniite, Ba2(Ti4+V3+)(As2O5)2OF, has been discovered in the Monte Arsiccio mine, Apuan Alps, Tuscany, Italy. It occurs as brown {001} tabular crystals, up to 1 mm across, with a vitreous lustre. It is brittle, with a perfect {001} cleavage. Streak is brownish. In reflected light, bianchiniite is grey, with orange–yellow internal reflections. It is weakly bireflectant, with a very weak anisotropy in shades of grey. Minimum and maximum reflectance data for COM wavelengths [Rmin/Rmax (%), (λ, nm)] are: 5.0/5.8 (470),5.7/6.5 (546), 5.7/7.0 (589) and 5.2/6.3 (650). Electron microprobe analyses gave (wt.% – average of 10 spot analyses): TiO2 10.34, V2O33.77, Fe2O3 3.76,As2O3 44.36, Sb2O3 0.22, SrO 0.45, BaO 34.79, PbO 0.28, F 1.77, sum 99.74, –O=F–0.75, total 98.99. On the basis of 12 anions per formula unit, the empirical formula of bianchiniite is (Ba2.00Sr0.04Pb0.02)Σ2.06(Ti4+1.14V3+0.44Fe3+0.42)Σ2.00[(As3.96Sb0.02)Σ3.98O10](O1.18F0.82)Σ2.00. Bianchiniite is tetragonal, space group I4/mcm, with unit-cell parameters a = 8.7266(4), c = 15.6777(7) Å, V = 1193.91(12) Å3 and Z = 8. Its crystal structure was refined from single-crystal X-ray diffraction data to R1 = 0.0134 on the basis of 555 unique reflections with Fo > 4σ(Fo)and 34 refined parameters. The crystal structure shows columns of corner-sharing [Ti/(V,Fe)]-centred octahedra running along c, connected along a and b through (As2O5) dimers. A {001} layer of Ba-centred [10+2]-coordinated polyhedra is intercalated between (As2O5) dimers. Bianchiniite has structural relations with fresnoite- and melilite-group minerals. The name honours the two mineral collectors Andrea Bianchini (b. 1959) and Mario Bianchini (b. 1962) for their contribution to the knowledge of the mineralogy of pyrite ± baryte ± iron-oxide ore deposits from the Apuan Alps.

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  • 15.
    Björling, Thomas
    et al.
    Stockholms universitet.
    Noréus, Dag
    Stockholms universitet.
    Jansson, Kjell
    Stockholms universitet.
    Andersson, Magnus
    Kungliga Tekniska Högskolan.
    Leonova, Ekaterina
    Stockholms universitet.
    Edén, Mattias
    Stockholms universitet.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Häussermann, Ulrich
    Stockholms universitet.
    SrAlSiH: A polyanionic semiconductor hydride2005In: Angewandte Chemie International Edition, ISSN 1433-7851, E-ISSN 1521-3773, Vol. 44, p. 7269-7273Article in journal (Refereed)
  • 16.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma.
    Andreozzi, Giovanni B.
    Sapienza Università di Roma.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Zn-O tetrahedral bond length variations in normal spinel oxides2011In: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 96, p. 594-598Article in journal (Refereed)
  • 17.
    Bosi, Ferdinando
    et al.
    Università di Roma, Italien.
    Andreozzi, Giovanni
    Università di Roma, Italien.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Experimental evidence for partial Fe2+ disorder at the Y and Z sites of tourmaline: a combined EMP, SREF, MS, IR and OAS study of schorl2015In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 79, no 3, p. 515-528Article in journal (Refereed)
  • 18.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma, Italy.
    Biagioni, Cristian
    Università di Pisa, Italy.
    Pezzotta, Federico
    Natural History Museum, Milan, Italy.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Cempírek, Jan
    Masaryk University, Brno, Czech Republic.
    Hawthorne, Frank C.
    University of Manitoba, Canada.
    Lussier, Aaron J.
    Univeristy of Manitoba, Canada.
    Abdu, Yassir A.
    University of Manitoba, Canada.
    Day, Maxwell C.
    University of Manitoba, Canada.
    Fayek, Mostafa
    University of Manitoba, Canada.
    Clark, Christine M.
    Eastern Michigan University, USA.
    Grice, Joel D.
    Canadian Museum of Nature, Ottawa, Canada.
    Henry, Darrell J.
    Lousiana State University, USA.
    Uvite, CaMg3(Al5Mg)(Si6O18)(BO3)3(OH)3(OH), a new, but long-anticipated mineral species of the tourmaline supergroup from San Piero in Campo, Elba Island, Italy2022In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 86, no 5, p. 767-776Article in journal (Refereed)
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  • 19.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma, Italy.
    Celata, Beatrice
    Sapienza Università di Roma, Italy.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Tempesta, Gioacchino
    University of Bari "Aldo Moro", Italy.
    Ciriotti, Marco
    University of Turin, Italy.
    Bittarello, Erica
    Univerity of Turin, Italy.
    Marengo, Alessandra
    Univerity of Turin, Italy.
    Mn-bearing purplish-red tourmaline from the Anjanabonoina pegmatite, Madagascar2021In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 85, no 2, p. 242-253Article in journal (Refereed)
    Abstract [en]

    A gem-quality purplish-red tourmaline sample of alleged liddicoatitic composition from the Anjanabonoina pegmatite, Madagascar, hasbeen fully characterised using a multi-analytical approach to define its crystal-chemical identity. Single-crystal X-ray diffraction, chem-ical and spectroscopic analysis resulted in the formula: X(Na0.410.35Ca0.24)Σ1.00Y(Al1.81Li1.00

    Fe3+0.04Mn3+0.02Mn2+0.12Ti0.004)Σ3.00

    ZAl6[T(Si5.60B0.406.00O18]

    (BO3)3(OH)3W[(OH)0.50F0.13O0.37]Σ1.00, which corresponds to the tourmaline species elbaite having the typical space group R3m and relatively small unit-cell dimensions, a= 15.7935(4) Å, c= 7.0860(2) Å and V= 7.0860(2) Å3.Optical absorption spectroscopy showed that the purplish-red colour is caused by minor amounts of Mn3+(Mn2O3= 0.20 wt.%).Thermal treatment in air up to 750°C strongly intensified the colour of the sample due to the oxidation of all Mn2+ to Mn3+ (Mn2O3 up to 1.21 wt.%). Based on infrared and Raman data, a crystal-chemical model regarding the electrostatic interaction betweenthe X cation and W anion, and involving the Y cations as well, is proposed to explain the absence or rarity of the mineral species ‘liddicoatite’.

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  • 20.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma, Italy.
    Christy, Andrew
    Australian National University, Canberra, Australia.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Crystal-chemical aspects of the roméite group, A2Sb2O6Y, of the pyrochlore supergroup2017In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 81, no 6, p. 1287-1302Article in journal (Refereed)
    Abstract [en]

    Four specimens of the roméite-group minerals oxyplumboroméite and fluorcalcioroméite from the Långban Mn-Fe deposit in Central Sweden were structurally and chemically characterized by single-crystal X-ray diffraction, electron microprobe analysis and infrared spectroscopy. The data obtained and those on additional roméite samples from literature show that the main structural variations within the roméite group are related to variations in the content of Pb2+, which is incorporated into the roméite structure via the substitution Pb2+ → A2+ where A2+ = Ca, Mn and Sr. Additionally, the cation occupancy at the six-fold coordinated B site, which is associated with the heterovalent substitution BFe3+ + Y□ → BSb5+ + YO2–, can strongly affect structural parameters.

    Chemical formulae of the roméite minerals group are discussed. According to crystal-chemical information, the species associated with the name ‘kenoplumboroméite’, hydroxycalcioroméite and fluorcalcioroméite most closely approximate end-member compositions Pb2(SbFe3+)O6□, Ca2(Sb5+Ti)O6(OH) and (CaNa)Sb2O6F, respectively. However, in accord with pyrochlore nomenclature rules, their names correspond to multiple end-members and are best described by the general formulae: (Pb,#)2(Sb,#)2O6□, (Ca,#)2(Sb,#)2O6(OH) and (Ca,#)Sb2(O,#)6F, where ‘#’ indicates an unspecified charge-balancing chemical substituent, including vacancies.

  • 21.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma, Italy.
    Cámara, Fernando
    Università di Torino, Italy.
    Ciriotti, Marco
    Associazione Micromineralogica Italiana, Torino, Italy.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Reznitskii, Leonid
    Russian Academy of Science, Irkutsk, Russia.
    Stagno, Vincenzo
    Sapienza Università di Roma, Italy.
    Crystal-chemical relations and classification problems in tourmalines belonging to the oxy-schorl—oxy-dravite—bosiite—povondraite series2017In: European journal of mineralogy, ISSN 0935-1221, E-ISSN 1617-4011, Vol. 29, no 3, p. 445-455Article in journal (Refereed)
  • 22.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma, Italy.
    Hatert, Frédéric
    Université de Liège, Belgium..
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Pasero, Marco
    Università di Pisa, Italy..
    Miyawaki, Ritsuro
    National Museum of Nature and Science, Tsukuba, Japan.
    Mills, Stuart J.
    Museum Victoria, Melbourne, Australia..
    On the application of the IMA-CNMNC dominant-valency rule to complex mineral compositions2019In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 83, no 5, p. 627-632Article in journal (Refereed)
    Abstract [en]

    Mineral species should be identified by an end-member formula and by using the dominant-valency rule as recommended by the IMA–CNMNC. However, the dominant-end-member approach has also been used in the literature. These two approaches generally converge, but for some intermediate compositions, significant differences between the dominant-valency rule and the dominant end-member approach can be observed. As demonstrated for garnet-supergroup minerals, for example, the end-member approach is ambiguous, as end-member proportions strongly depend on the calculation sequence. For this reason, the IMA–CNMNC strongly recommends the use of the dominant-valency rule for mineral nomenclature, because it alone may lead to unambiguous mineral identification. Although the simple application of the dominant-valency rule is successful for the identification of many mineral compositions, sometimes it leads to unbalanced end-member formulae, due to the occurrence of a coupled heterovalent substitution at two sites along with a heterovalent substitution at a single site. In these cases, it may be useful to use the site-total-charge approach to identify the dominant root-charge arrangement on which to apply the dominant-constituent rule. The dominant-valency rule and the site-totalcharge approach may be considered two procedures complementary to each other for mineral identification. Their critical point is to find the most appropriate root-charge and atomic arrangements consistent with the overriding condition dictated by the end-member formula. These procedures were approved by the IMA−CNMNC in May 2019.

  • 23.
    Bosi, Ferdinando
    et al.
    Sapienza University, Rome, Italy.
    Hatert, Frédéric
    Université de Liège, Belgium..
    Pasero, Marco
    Università di Pisa, Italy..
    Mills, Stuart J.
    Museum Victoria, Melbourne, Australia..
    Miyawaki, Ritsuro
    National Museum of Nature and Science, Tsukuba, Japan.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    A brief comment on Hawthorne (2023): “On the definition of distinct mineral species: A critique of current IMA-CNMNC procedures”2023In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 87, no 3, p. 505-507Article in journal (Refereed)
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  • 24.
    Bosi, Ferdinando
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Andreozzi, Giovanni B.
    Sapienza Università di Roma.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Lucchesi, Sergio
    Sapienza Università di Roma.
    Structural refinement of Mn-doped spinel: a case for tetrahedrally coordinated Mn3+ in an oxygen-based structure2007In: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 92, p. 27-33Article in journal (Refereed)
  • 25.
    Bosi, Ferdinando
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    D'Ippolito, Veronica
    Sapienza Università di Roma.
    Andreozzi, Giovanni B.
    Sapienza Università di Roma.
    Blue spinel crystals in the MgAl2O4-CoAl2O4 series: II. Cation ordering over short range and long range scales2012In: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 97, p. 1834-1840Article in journal (Refereed)
  • 26.
    Bosi, Ferdinando
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Crystal chemistry of the magnetite-ulvöspinel series2009In: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 94, p. 181-189Article in journal (Refereed)
  • 27.
    Bosi, Ferdinando
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Crystal chemistry of the MgAl2O4-MgMn2O4-MnMn2O4 system: Analysis of structural distortion in spinel and hausmannite-type structures2010In: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 95, p. 602-607Article in journal (Refereed)
  • 28.
    Bosi, Ferdinando
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Crystal chemistry of the ulvöspinel-qandilite series2014In: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 99, p. 847-851Article in journal (Refereed)
  • 29.
    Bosi, Ferdinando
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Stoichiometry of synthetic ulvöspinel single crystals2008In: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 93, p. 1312-1316Article in journal (Refereed)
  • 30.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma, Italy.
    Naitza, Stefano
    Università degli Studi di Cagliari, Italy.
    Secchi, Francesco
    Università degli Studi di Sassari, Italy.
    Conte, Aida M.
    CNR, Sede Secondaria di Roma "Sapienza", Roma, Italy.
    Cuccuru, Stefano
    Università degli Studi di Sassari, Italy.
    Andreozzi, Giovanni B.
    Sapienza Università di Roma, Italy.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Petrogenic controls on the origin of tourmalinite veins from Mandrolisai igneous massif (central Sardinia, Italy): Insights from tourmaline crystal chemistry2019In: Lithos, ISSN 0024-4937, E-ISSN 1872-6143, Vol. 342-343, p. 333-344Article in journal (Refereed)
  • 31.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma, Italy.
    Naitza, Stefano
    Università degli Studi di Cagliari, Italy.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Secchi, Francesco
    Università degli Studi di Sassari, Italy.
    Conte, Aida M.
    CNR-Istituto di Georiscienze e Georisose, Rome, Italy.
    Cuccuru, Stafano
    Università degli Studi di Sassari.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    De La Rosa, Nathaly
    Division of Nuclear Physics, Lund University.
    Kristiansson, Per
    Division of Nuclear Physics, Lund University.
    Nilsson, E.J. Charlotta
    Division of Nuclear Physics, Lund University.
    Ros, Linus
    Division of Nuclear Physics, Lund University.
    Andreozzi, Giovanni B.
    Sapienza Università di Roma, Italy.
    Late magmatic controls on the origin of schorlitic and foititic tourmalines from late-Variscan peraluminous granites of the Arbus pluton (SW Sardinia, Italy): Crystal-chemical study and petrological constraints2018In: Lithos, ISSN 0024-4937, E-ISSN 1872-6143, Vol. 308-309, p. 395-411Article in journal (Refereed)
    Abstract [en]

    Tourmalines from the late-Variscan Arbus pluton (SWSardinia) and its metamorphic aureole were structurally and chemically characterized by single-crystal X-ray diffraction, electron and nuclear microprobe analysis, Mössbauer, infrared and optical absorption spectroscopy, to elucidate their origin and relationships with the magmatic evolution during the pluton cooling stages. The Arbus pluton represents a peculiar shallow magmatic system, characterized by sekaninaite (Fe-cordierite)-bearing peraluminous granitoids, linked via AFC processes to gabbroic mantle-derived magmas. The Fe2+-Al-dominant tourmalines occur in: a) pegmatitic layers and pods, as prismatic crystals; b) greisenized rocks and spotted granophyric dikes, as clots or nests of fine-grained crystals in small miaroles locally forming orbicules; c) pegmatitic veins and pods close to the contacts within the metamorphic aureole. Structural formulae indicate that tourmaline in pegmatitic layers is schorl, whereas in greisenized rocks it ranges fromschorl to fluor-schorl. Tourmalines in thermometamorphosed contact aureole are schorl, foitite and Mg-rich oxy-schorl. The main substitution is Na+Fe2+↔▢+Al, which relates schorl to foitite. The homovalent substitution (OH)F at the O1 crystallographic site relates schorl to fluor-schorl, while the heterovalent substitution Fe2++(OH, F)Al+O relates schorl/fluor-schorl to oxy-schorl. Tourmaline crystallization in the Arbus pluton was promoted by volatile (B, F and H2O) enrichment, low oxygen fugacity and Fe2+ activity. The mineralogical evolutive trend is driven by decreasing temperature, as follows: sekaninaite+quartz →schorl+quartz→fluor-schorl+quartz → foitite+quartz. The schorl→foitite evolution represents a distinct trend towards (Al+!) increase and unit-cell volumedecrease. These trends are typical of granitic magmas and consistent with Li-poor granitic melts, as supported by the absence of elbaite and other Li-minerals in the Arbus pluton. Tourmaline-bearing rocks reflect the petrogenetic signi!cance of contribution from a metapelitic crustal component during the evolution of magmas in the middle-upper crust.

  • 32.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma, Italy.
    Pezzotta, Federico
    Natural History Museum, Milano, Italy.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Altieri, Alessandra
    Sapienza Università di Roma, Italy.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Tempesta, Gioacchino
    Univeristy of Bari, Italy.
    Cempírek, Jan
    Masaryk University, Brno, Czech Republic.
    Princivalleite, Na(Mn2Al)Al6(Si6O18)(BO3)3(OH)3O, a new mineral species of the tourmaline supergroup from Veddasca Valley, Varese, Italy2022In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 86, no 1, p. 78-86Article in journal (Refereed)
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  • 33.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma, Italy.
    Reznitskii, Leonid
    Russian Academy of Science, Irkutsk, Russia.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Crystal chemistry of Al-V-Cr oxy-tourmalines from Sludyanka complex, Lake Baikal, Russia2017In: European journal of mineralogy, ISSN 0935-1221, E-ISSN 1617-4011, Vol. 29, no 3, p. 457-472Article in journal (Refereed)
  • 34.
    Bosi, Ferdinando
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Reznitskii, Leonid
    Russian Academy of Science.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Vanadio-oxy-chromium-dravite, NaV3(Cr4Mg2)(Si6O18)(BO3)3(OH)3O, a new mineral species of the tourmaline supergroup 2014In: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 99, p. 1155-1162Article in journal (Refereed)
  • 35.
    Bosi, Ferdinando
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Reznitskii, Leonid
    Russian Academy of Science, Irkutsk.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Vanadio-oxy-dravite, NaV3(Al4Mg2)(Si6O18)(BO3)3(OH)3O, a new mineral species of the tourmaline supergroup2014In: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 99, p. 218-224Article in journal (Refereed)
  • 36.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma, Italy.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Fregola, Rosa Anna
    Università di Bari Aldo Moro, Italy.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Crystal chemistry of spinels in the system MgAl2O4-MgV2O4-Mg2VO42016In: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 101, p. 580-586Article in journal (Refereed)
    Abstract [en]

    Eight spinel single-crystal samples belonging to the spinel sensu stricto-magnesiocoulsonite series (MgAl2O4-MgV2O4) were synthesized and crystal-chemically characterized by X‑ray diffraction, electron microprobe and optical absorption spectroscopy. Site populations show that the tetrahedrally coordinated site (T) is populated by Mg and minor Al for the spinel sensu stricto compositions, and only by Mg for the magnesiocoulsonite compositions, while the octahedrally coordinated site (M) is populated by Al, V3+, minor Mg, and very minor amounts of V4+. The latter occurs in appreciable amounts in the Al-free magnesium vanadate spinel, T(Mg)M(Mg0.26V3+1.48V4+0.26)O4, showing the presence of the inverse spinel VMg2O4. The studied samples are characterized by substitution of Al3+ for V3+ and (Mg2++V4+) for 2V3+ described in the system MgAl2O4-MgV2O4-VMg2O4.

    The present data in conjunction with data from the literature provide a basis for quantitative analyses of two solid-solution series MgAl2O4-MgV23+O4 and MgV23+O4-V4+Mg2O4. Unit-cell parameter increases with increasing V3+ along the series MgAl2O4-MgV2O4 (8.085–8.432 Å), but only slightly increases with increasing V3+ along the series VMg2O4-MgV2O4 (8.386–8.432 Å). Although a solid solution could be expected between the MgAl2O4 and VMg2O4 end-members, no evidence was found. Amounts of V4+ are nearly insignificant in all synthetic Al-bearing vanadate spinels, but are appreciable in Al-free vanadate spinel.

    An interesting observation of the present study is that despite the observed complete solid-solution along the MgAl2O4-MgV2O4 and MgV2O4-VMg2O4 series, the spinel structure seems to be unable to stabilize V4+ in any intermediate members on the MgAl2O4-Mg2VO4 join even at high oxygen fugacities. This behavior indicates that the accommodation of specific V-valences can be strongly influenced by crystal-structural constraints, and any evaluation of oxygen fugacities during mineral formation based exclusively on V cation valence distributions in spinel should be treated with caution. The present study underlines that the V valency distribution in spinels is not exclusively reflecting oxygen fugacities, but also depends on activities and solubilities of all chemical components in the crystallization environment.

  • 37.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma, Italy.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Oxy-foitite, □(Fe2+Al2)Al6(Si6O18)(BO3)3(OH)3O, a new mineral species of the tourmaline supergroup2017In: European journal of mineralogy, ISSN 0935-1221, E-ISSN 1617-4011, Vol. 29, no 5, p. 889-896Article in journal (Refereed)
    Abstract [en]

    Oxy-foitite, □(Fe2+Al2)Al6(Si6O18)(BO3)3(OH)3O, is a new mineral of the tourmaline supergroup. It occurs in high-grade migmatitic gneisses of pelitic composition at the Cooma metamorphic Complex (New South Wales, Australia), in association with muscovite, K-feldspar and quartz. Crystals are black with a vitreous luster, sub-conchoidal fracture and gray streak. Oxy-foitite has a Mohs hardness of ∼7, and has a calculated density of 3.143 g/cm3. In plane-polarized light, oxy-foitite is pleochroic (O= dark brown and E = pale brown), uniaxial negative. Oxy-foitite belongs to the trigonal crystal system, space group R3ma = 15.9387(3) Å, c = 7.1507(1)Å and V = 1573.20(6)Å3,Z = 3. The crystal structure of oxy-foitite was refined to R1 = 1.48% using 3247 unique reflections from single-crystal X-ray diffraction using MoKα radiation. Crystal-chemical analysis resulted in the empirical structural formula: X(□0.53Na0.45Ca0.01K0.01)Σ1.00Y(Al1.53Fe2+1.16Mg0.22Mn2+0.05Zn0.01Ti4+0.03)Σ3.00Z(Al5.47Fe3+0.14Mg0.39)Σ6.00[(Si5.89Al0.11)Σ6.00O18](BO3)3V(OH)3W[O0.57F0.04(OH)0.39]Σ1.00. Oxy-foitite belongs to the X-site vacant group of the tourmaline-supergroup minerals, and shows chemical relationships with foitite through the substitution YAl3++WO2-YFe2++W(OH)1–.

  • 38.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma, Rome, Italy.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Thermally induced cation redistribution in Fe‑bearing oxy‑dravite and potential geothermometric implications2016In: Contributions to Mineralogy and Petrology, ISSN 0010-7999, E-ISSN 1432-0967, Vol. 171, no 5, p. 1-14, article id 47Article in journal (Refereed)
    Abstract [en]

    Iron-bearing oxy-dravite was thermally treated in air and hydrogen atmosphere at 800 °C to study potential changes in Fe, Mg and Al ordering over the octahedrally coordinated Y and Z sites and to explore possible applications to intersite geothermometry based on tourmaline. Overall, the experimental data (structural refinement, Mössbauer, infrared and optical absorption spectroscopy) show that heating Fe-bearing tourmalines results in disordering of Fe over Y and Z balanced by ordering of Mg at Y, whereas Al does not change appreciably. The Fe disorder depends on temperature, but less on redox conditions. The degree of Fe3+–Fe2+ reduction is limited despite strongly reducing conditions, indicating that the fO2 conditions do not exclusively control the Fe oxidation state at the present experimental conditions. Untreated and treated samples have similar short- and long-range crystal structures, which are explained by stable Al-extended clusters around the O1 and O3 sites. In contrast to the stable Al clusters that preclude any temperature-dependent Mg–Al order– disorder, there occurs Mg diffusion linked to temperaturedependent exchange with Fe. Ferric iron mainly resides around O2− at O1 rather than (OH), but its intersite disorder induced by thermal treatment indicates that Fe redistribution is the driving force for Mg–Fe exchange and that its diffusion rates are significant at these temperatures. With increasing temperature, Fe progressively disorders over Y and Z, whereas Mg orders at Y according to the order–disorder reaction: YFe + ZMg → ZFe + YMg. The presented findings are important for interpretation of the post-crystallization history of both tourmaline and tourmaline host rocks and imply that successful tourmaline geothermometers may be developed by thermal calibration of the Mg– Fe order–disorder reaction, whereas any thermometers based on Mg–Al disorder will be insensitive and involve large uncertainties.

  • 39.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma, Italy.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Thermally induced cation redistribution in fluor-elbaite and Fe-bearing tourmalines2019In: Physics and chemistry of minerals, ISSN 0342-1791, E-ISSN 1432-2021, Vol. 46, no 4, p. 371-383Article in journal (Refereed)
  • 40.
    Bosi, Ferdinando
    et al.
    Sapienza Università di Roma, Italy.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Ciriotti, Marco
    Associazione Micromineralogica Italiana,Torino, Italy.
    Experimental cation redistribution in the tourmaline lucchesiite, CaFe2+3Al6(Si6O18)(BO3)3(OH)3O2018In: Physics and chemistry of minerals, ISSN 0342-1791, E-ISSN 1432-2021, Vol. 45, no 7, p. 621-632Article in journal (Refereed)
    Abstract [en]

    Natural Mg-rich lucchesiite was thermally treated in air and hydrogen atmosphere up to 800 °C to study potential changes in Fe-, Mg- and Al ordering over the octahedrally coordinated Y-  and Z -sites, and to explore possible applications to intracrystalline geothermometry based on tourmaline. Overall, the experimental data (structural refinement, Mössbauer, infrared and optical absorption spectroscopy) show that thermal treatment of lucchesiite results in an increase of Fetot contents at Z balanced by an increase of Mg and Al at Y . This process is accompanied by a significant deprotonation of the O3 anion site. The Fe order–disorder reaction depends more on temperature, than on redox conditions. During heat treatment in H2 ,reduction of Fe3+ to Fe2+ was not observed despite strongly reducing conditions, indicating that the fO2  conditions do not exclusively control the Fe oxidation state at the present experimental conditions. On the basis of this and previous studies, the intersite order–disorder process induced by thermal treatment indicates that Fe redistribution is an important factor for Fe–Mg–Al-exchange and is significant at temperatures around 800 °C. As a result, Fe–Mg–Al intersite order–disorder is sensitive to temperature variations, whereas geothermometers based solely on Mg–Al order–disorder appear insensitive and involve large uncertainties. The presented findings are important for interpretation of the post-crystallization history of both tourmaline and tourmaline host rocks, and indicate that successful tourmaline geothermometers may be developed by thermal calibration of the Fe-Mg–Al order–disorder reaction.

  • 41. Bosi, Ferdinando
    et al.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Ciriotti, Marco E.
    Università di Torino, Italy.
    Mills, Stuart J.
    Geosciences, Museums Victoria, Melbourne, Australia.
    Lowering R3m Symmetry in Mg-Fe-Tourmalines: The Crystal Structures of Triclinic Schorl and Oxy-Dravite, and the Mineral luinaite-(OH) Discredited2022In: Minerals, E-ISSN 2075-163X, Vol. 12, no 4, p. 1-10, article id 430Article in journal (Refereed)
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  • 42.
    Bosi, Ferdinando
    et al.
    Swedish Museum of Natural History, Department of Geology.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Reznitskii, Leonid
    Russian Academy of Science, Irkutsk.
    Crystallographic and spectroscopic characterization of Fe-bearing chromo-alumino-povondraite and its relationships with oxy-chromium-dravite and oxy-dravite2013In: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 98, p. 1557-1564Article in journal (Refereed)
  • 43.
    Bruschini, Enrico
    et al.
    Sapienza Università di Roma.
    Speziale, Sergio
    Geoforschungszentrum, Potsdam.
    Andreozzi, Giovanni
    Sapienza Università di Roma.
    Bosi, Ferdinando
    Sapienza Università di Roma.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    The elasticity of MgAl2O4-MnAl2O4 spinels by Brillouin scattering and an empirical approach for bulk modulus prediction2015In: American Mineralogist, ISSN 0003-004X, E-ISSN 1945-3027, Vol. 100, p. 644-651Article in journal (Refereed)
  • 44.
    Cooper, Mark
    et al.
    University of Manitoba, Winnipeg, Canada.
    Hawthorne, Frank
    University of Manitoba, Winnipeg, Canada.
    Langhof, Jörgen
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Holtstam, Dan
    Swedish Museum of Natural History, Department of Geology.
    Wiklundite, ideally Pb2[4](Mn2+,Zn)3(Fe3+,Mn2+)2(Mn2+,Mg)19(As3+O3)2[(Si,As5+)O4]6 (OH)18Cl6, a new mineral from Långban, Filipstad, Värmland, Sweden: Description and crystal structure2017In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 81, no 4, p. 841-855Article in journal (Refereed)
  • 45.
    Cámara, Fernando
    et al.
    Università degli Studi di Milano, Italy.
    Baratelli, Lisa
    Università degli Studi di Milano, Italy.
    Ciriotti, Marco E.
    Università degli Studi di Torino, Italy.
    Nestola, Fabrizio
    Università degli Studi di Padova, Italy.
    Piccoli, Gian Carlo
    Associazione Micromineralogica Italiana, Alba, Italy.
    Bosi, Ferdinando
    Sapienza Università di Roma, Italy.
    Bittarello, Erica
    Università degli Studi di Torino, Italy.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Balestra, Corrado
    Associazione Micromineralogica Italiana, Savona, Italy.
    As-bearing new mineral species from Valletta mine, Maira Valley, Piedmont, Italy: IV. Lombardoite, Ba2Mn3+(AsO4)2(OH) and aldomarinoite, Sr2Mn3+(AsO4)2(OH), description and crystal structure2022In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 86, no 3, p. 447-458Article in journal (Refereed)
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    fulltext
  • 46.
    Cámara, Fernando
    et al.
    Università di Milano, Italy.
    Biagioni, Cristian
    Università di Pisa, Italy.
    Ciriotti, Marco E.
    Università di Torino, Italy.
    Bosi, Ferdinando
    Sapienza Università di Roma, Italy.
    Kolitsch, Uwe
    Universität Wien, Austria.
    Paar, Werner H.
    Universität Salzburg, Austria.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Lepore, Giovanni O.
    Università di Firenze, Italy.
    Blass, Günter
    Bittarello, Erica
    Università di Torino, Italy.
    Piccoliite, NaCaMn3+2(AsO4)2O(OH), a new arsenate from the manganese deposits of Montaldo di Mondovì and Valletta, Piedmont, Italy2023In: Mineralogical magazine, ISSN 0026-461X, E-ISSN 1471-8022, Vol. 87, no 2, p. 204-217Article in journal (Refereed)
    Download full text (pdf)
    fulltext
  • 47.
    Cámara, Fernando
    et al.
    University of Milan, Italy.
    Bosi, Ferdinando
    Sapienza Università di Roma, Italy.
    Skogby, Henrik
    Swedish Museum of Natural History, Department of Geology.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Celata, Beatrice
    Sapienza Università di Roma, Italy.
    Ciriotti, Marco
    Università di Torino, Italy.
    Schorl-1A from Langesundsfjord (Norway)2022In: Journal of Geosciences, ISSN 1802-6222, E-ISSN 1803-1943, Vol. 67, no 2, p. 129-139Article in journal (Refereed)
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    fulltext
  • 48. Deegan, F.M.
    et al.
    Whitehouse, Martin J.
    Swedish Museum of Natural History, Department of Geology.
    Troll, V.R.
    Budd, D.A.
    Harris, C.
    Geiger, H.
    Hålenius, U.
    Swedish Museum of Natural History, Department of Geology.
    Pyroxene standards for SIMS oxygen isotope analysis and their application to Merapi volcano, Sunda arc, Indonesia2016In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 447, p. 1-10Article in journal (Refereed)
    Abstract [en]

    Measurement of oxygen isotope ratios in common silicate minerals such as olivine, pyroxene, feldspar, garnet, and quartz is increasingly performed by Secondary Ion Mass Spectrometry (SIMS). However, certain mineral groups exhibit solid solution series, and the large compositional spectrum of these mineral phases will result in matrix effects during SIMS analysis. These matrix effects must be corrected through repeated analysis of compositionally similar standards to ensure accurate results. In order to widen the current applicability of SIMS to solid solution mineral groups in common igneous rocks, we performed SIMS homogeneity tests on new augite (NRM-AG-1) and enstatite (NRM-EN-2) reference materials sourced from Stromboli, Italy and Webster, North Carolina, respectively. Aliquots of the standard minerals were analysed by laser fluorination (LF) to establish their δ18O values. Repeated SIMS measurements were then performed on randomly oriented fragments of the same pyroxene crystals, which yielded a range in δ18O less than ± 0.42 and ± 0.58‰ (2σ) for NRM-AG-1 and NRM-EN-2, respectively. Homogeneity tests verified that NRM-AG-1 and NRM-EN-2 do not show any crystallographic orientation bias and that they are sufficiently homogeneous on the 20 μm scale to be used as routine mineral standards for SIMS δ18O analysis. We subsequently tested our new standard materials on recently erupted pyroxene crystals from Merapi volcano, Indonesia. The δ18O values for Merapi pyroxene obtained by SIMS (n = 204) agree within error with the LF-derived δ18O values for Merapi pyroxene but differ from bulk mineral and whole-rock data obtained by conventional fluorination. The bulk samples are offset to higher δ18O values as a result of incorporation of mineral and glass inclusions that in part reflects crustal contamination processes. The Merapi pyroxene SIMS data, in turn, display a frequency peak at 5.8‰, which allows us to estimate the δ18O value of the primary mafic magma at Merapi to ~ 6.1‰ when assuming closed system differentiation.

  • 49.
    Dekov, Vesselin
    et al.
    University of Sofia.
    Boycheva, Tanya
    University of Sofia.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Billström, Kjell
    Swedish Museum of Natural History, Department of Geology.
    Kamenov, George D.
    University of Florida.
    Shanks, Wayne C.
    U.S. Geological Survey, Denver.
    Stummeyer, Jens
    Bundesanstalt für Geowissenschaften, Hannover.
    Mineralogical and geochemical evidence for recent hydrothermal activity at the west wall of 12°50´N core complex (Mid-Atlantic Ridge): a new ultramafic-hosted seafloor hydrothermal deposit?2011In: Marine Geology, ISSN 0025-3227, E-ISSN 1872-6151, Vol. 288, p. 90-102Article in journal (Refereed)
  • 50.
    Dekov, Vesselin
    et al.
    University of Sofia.
    Boycheva, Tanya
    University of Sofia.
    Hålenius, Ulf
    Swedish Museum of Natural History, Department of Geology.
    Petersen, Sven
    Leibiz-Institut für Meeresforschung, IFM-GEOMAR.
    Billström, Kjell
    Swedish Museum of Natural History, Department of Geology.
    Stummeyer, Jens
    Bundesanstalt für Geowissenschaften und Rohstoffe, Hannover.
    Kamenov, George
    University of Florida.
    Shanks, Wayne
    U.S. Geological Survey, Denver.
    Atacamite and paratacamite from the ultramafic-hosted Logatchev seafloor vent field (14°45´ N, Mid-Atlantic Ridge)2011In: Chemical Geology, ISSN 0009-2541, E-ISSN 1872-6836, Vol. 286, p. 169-184Article in journal (Refereed)
123 1 - 50 of 139
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