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Paola Bonazzi - One of the best experts on this subject based on the ideXlab platform.

  • a multimethodic approach for the characterization of manganiceladonite a new member of the celadonite family from cerchiara mine eastern liguria italy
    Mineralogical Magazine, 2017
    Co-Authors: Giovanni Orazio Lepore, Luca Bindi, F Di Benedetto, Enrico Mugnaioli, Cecilia Viti, Alberto Zanetti, Marco E Ciriotti, Paola Bonazzi
    Abstract:

    In the manganesiferous ores associated with the metacherts of the ophiolitic sequences at the Cerchiara mine, Eastern Liguria (Italy), a new Mn-bearing mineral belonging to the Mica Group has been recently found and characterized. High resolution transmission electron microscopy and electron diffraction tomography studies confirm that the mineral belongs to the Mica Group. Unit-cell parameters from the powder diffraction pattern are: a = 5.149(1), b = 8.915(1), c = 10.304(1) A, β = 102.03(1)°, space Group C 2 or C 2/ m . On the basis of the electron paramagnetic resonance spectroscopic results, the Mn4+ content represents a very subordinate fraction of the total Mn, the remaining occurring as Mn3+. The Raman spectrum clearly indicates the presence of OH Groups in the structure. Laser-ablation inductively-coupled-plasma mass-spectrometry measurements assess the presence of considerable amounts of Li. Assuming all Mn as Mn3+ and 22 negative charges, the empirical formula can be expressed as: (K0.83□0.17)(![Graphic][1] Mg0.80Li0.20![Graphic][2] )(Si3.89Al0.10)O10[(OH)1.92F0.08] with the sum of the octahedral cations indicating a ‘transitional’ character between a di- and a tri-octahedral structure. This formula corresponds ideally to the Mn3+ analogue of celadonite, thus expanding the range of solid solution in the celadonite family. The ideal end-member formula KMn3+MgSi4O10(OH)2 can be easily related to celadonite by the homovalent substitution VIMn3+ → VIFe3+. The mineral and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association, (IMA 2015-052). [1]: /embed/inline-graphic-1.gif [2]: /embed/inline-graphic-2.gif

  • balestraite kli2vsi4o10o2 the first member of the Mica Group with octahedral v5
    American Mineralogist, 2015
    Co-Authors: Giovanni Orazio Lepore, Luca Bindi, Alberto Zanetti, Marco E Ciriotti, Olaf Medenbach, Paola Bonazzi
    Abstract:

    A Mica-Group mineral characterized by a high V content and free of Al was found in the manganesiferous beds within the metacherts of the ophiolitic sequences at the Cerchiara mine, Eastern Liguria (Italy), in association with hematite, quartz, and calcite. CheMical and structural characterization supported by Raman data defines this phase as a new mineral species, which is named balestraite after Corrado Balestra, a prominent Italian amateur mineralogist. Balestraite, ideally KLi2V5+Si4O10O2, is a 1 M trioctahedral Mica crystallizing in the C 2 space Group, with a = 5.2024(5), b = 8.9782(7), c = 9.997(2) A, β = 100.40(2)°, V = 459.3(1) A3, Z = 2. The reduction of symmetry from the “ideal” space Group C 2/ m is related to the ordering of V at only one of the two pseudo-symmetric octahedral sites. Vanadium forms very distorted octahedra with a [2+2+2] geometry characteristic of the valence state +5. The Li,V composition of the octahedral sheet, the pure tetrasilicic character of the tetrahedral sheet, and the anhydrous character produce unusual geometrical features for this Mica. The occurrence of 5+ as the dominant valence state of V and the virtually complete O2− → OH− substitution at the O4 site indicate strongly oxidizing conditions of crystallization, which are consistent with balestraite occurring at the boundary between carbonate-bearing veins and hematite bands. The new mineral and name were approved by the Commission on New Minerals, Nomenclature and Classification, IMA (2013-080).

Giovanni Orazio Lepore - One of the best experts on this subject based on the ideXlab platform.

  • a multimethodic approach for the characterization of manganiceladonite a new member of the celadonite family from cerchiara mine eastern liguria italy
    Mineralogical Magazine, 2017
    Co-Authors: Giovanni Orazio Lepore, Luca Bindi, F Di Benedetto, Enrico Mugnaioli, Cecilia Viti, Alberto Zanetti, Marco E Ciriotti, Paola Bonazzi
    Abstract:

    In the manganesiferous ores associated with the metacherts of the ophiolitic sequences at the Cerchiara mine, Eastern Liguria (Italy), a new Mn-bearing mineral belonging to the Mica Group has been recently found and characterized. High resolution transmission electron microscopy and electron diffraction tomography studies confirm that the mineral belongs to the Mica Group. Unit-cell parameters from the powder diffraction pattern are: a = 5.149(1), b = 8.915(1), c = 10.304(1) A, β = 102.03(1)°, space Group C 2 or C 2/ m . On the basis of the electron paramagnetic resonance spectroscopic results, the Mn4+ content represents a very subordinate fraction of the total Mn, the remaining occurring as Mn3+. The Raman spectrum clearly indicates the presence of OH Groups in the structure. Laser-ablation inductively-coupled-plasma mass-spectrometry measurements assess the presence of considerable amounts of Li. Assuming all Mn as Mn3+ and 22 negative charges, the empirical formula can be expressed as: (K0.83□0.17)(![Graphic][1] Mg0.80Li0.20![Graphic][2] )(Si3.89Al0.10)O10[(OH)1.92F0.08] with the sum of the octahedral cations indicating a ‘transitional’ character between a di- and a tri-octahedral structure. This formula corresponds ideally to the Mn3+ analogue of celadonite, thus expanding the range of solid solution in the celadonite family. The ideal end-member formula KMn3+MgSi4O10(OH)2 can be easily related to celadonite by the homovalent substitution VIMn3+ → VIFe3+. The mineral and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association, (IMA 2015-052). [1]: /embed/inline-graphic-1.gif [2]: /embed/inline-graphic-2.gif

  • balestraite kli2vsi4o10o2 the first member of the Mica Group with octahedral v5
    American Mineralogist, 2015
    Co-Authors: Giovanni Orazio Lepore, Luca Bindi, Alberto Zanetti, Marco E Ciriotti, Olaf Medenbach, Paola Bonazzi
    Abstract:

    A Mica-Group mineral characterized by a high V content and free of Al was found in the manganesiferous beds within the metacherts of the ophiolitic sequences at the Cerchiara mine, Eastern Liguria (Italy), in association with hematite, quartz, and calcite. CheMical and structural characterization supported by Raman data defines this phase as a new mineral species, which is named balestraite after Corrado Balestra, a prominent Italian amateur mineralogist. Balestraite, ideally KLi2V5+Si4O10O2, is a 1 M trioctahedral Mica crystallizing in the C 2 space Group, with a = 5.2024(5), b = 8.9782(7), c = 9.997(2) A, β = 100.40(2)°, V = 459.3(1) A3, Z = 2. The reduction of symmetry from the “ideal” space Group C 2/ m is related to the ordering of V at only one of the two pseudo-symmetric octahedral sites. Vanadium forms very distorted octahedra with a [2+2+2] geometry characteristic of the valence state +5. The Li,V composition of the octahedral sheet, the pure tetrasilicic character of the tetrahedral sheet, and the anhydrous character produce unusual geometrical features for this Mica. The occurrence of 5+ as the dominant valence state of V and the virtually complete O2− → OH− substitution at the O4 site indicate strongly oxidizing conditions of crystallization, which are consistent with balestraite occurring at the boundary between carbonate-bearing veins and hematite bands. The new mineral and name were approved by the Commission on New Minerals, Nomenclature and Classification, IMA (2013-080).

Enrico Mugnaioli - One of the best experts on this subject based on the ideXlab platform.

  • a multimethodic approach for the characterization of manganiceladonite a new member of the celadonite family from cerchiara mine eastern liguria italy
    Mineralogical Magazine, 2017
    Co-Authors: Giovanni Orazio Lepore, Luca Bindi, F Di Benedetto, Enrico Mugnaioli, Cecilia Viti, Alberto Zanetti, Marco E Ciriotti, Paola Bonazzi
    Abstract:

    In the manganesiferous ores associated with the metacherts of the ophiolitic sequences at the Cerchiara mine, Eastern Liguria (Italy), a new Mn-bearing mineral belonging to the Mica Group has been recently found and characterized. High resolution transmission electron microscopy and electron diffraction tomography studies confirm that the mineral belongs to the Mica Group. Unit-cell parameters from the powder diffraction pattern are: a = 5.149(1), b = 8.915(1), c = 10.304(1) A, β = 102.03(1)°, space Group C 2 or C 2/ m . On the basis of the electron paramagnetic resonance spectroscopic results, the Mn4+ content represents a very subordinate fraction of the total Mn, the remaining occurring as Mn3+. The Raman spectrum clearly indicates the presence of OH Groups in the structure. Laser-ablation inductively-coupled-plasma mass-spectrometry measurements assess the presence of considerable amounts of Li. Assuming all Mn as Mn3+ and 22 negative charges, the empirical formula can be expressed as: (K0.83□0.17)(![Graphic][1] Mg0.80Li0.20![Graphic][2] )(Si3.89Al0.10)O10[(OH)1.92F0.08] with the sum of the octahedral cations indicating a ‘transitional’ character between a di- and a tri-octahedral structure. This formula corresponds ideally to the Mn3+ analogue of celadonite, thus expanding the range of solid solution in the celadonite family. The ideal end-member formula KMn3+MgSi4O10(OH)2 can be easily related to celadonite by the homovalent substitution VIMn3+ → VIFe3+. The mineral and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association, (IMA 2015-052). [1]: /embed/inline-graphic-1.gif [2]: /embed/inline-graphic-2.gif

Alberto Zanetti - One of the best experts on this subject based on the ideXlab platform.

  • a multimethodic approach for the characterization of manganiceladonite a new member of the celadonite family from cerchiara mine eastern liguria italy
    Mineralogical Magazine, 2017
    Co-Authors: Giovanni Orazio Lepore, Luca Bindi, F Di Benedetto, Enrico Mugnaioli, Cecilia Viti, Alberto Zanetti, Marco E Ciriotti, Paola Bonazzi
    Abstract:

    In the manganesiferous ores associated with the metacherts of the ophiolitic sequences at the Cerchiara mine, Eastern Liguria (Italy), a new Mn-bearing mineral belonging to the Mica Group has been recently found and characterized. High resolution transmission electron microscopy and electron diffraction tomography studies confirm that the mineral belongs to the Mica Group. Unit-cell parameters from the powder diffraction pattern are: a = 5.149(1), b = 8.915(1), c = 10.304(1) A, β = 102.03(1)°, space Group C 2 or C 2/ m . On the basis of the electron paramagnetic resonance spectroscopic results, the Mn4+ content represents a very subordinate fraction of the total Mn, the remaining occurring as Mn3+. The Raman spectrum clearly indicates the presence of OH Groups in the structure. Laser-ablation inductively-coupled-plasma mass-spectrometry measurements assess the presence of considerable amounts of Li. Assuming all Mn as Mn3+ and 22 negative charges, the empirical formula can be expressed as: (K0.83□0.17)(![Graphic][1] Mg0.80Li0.20![Graphic][2] )(Si3.89Al0.10)O10[(OH)1.92F0.08] with the sum of the octahedral cations indicating a ‘transitional’ character between a di- and a tri-octahedral structure. This formula corresponds ideally to the Mn3+ analogue of celadonite, thus expanding the range of solid solution in the celadonite family. The ideal end-member formula KMn3+MgSi4O10(OH)2 can be easily related to celadonite by the homovalent substitution VIMn3+ → VIFe3+. The mineral and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association, (IMA 2015-052). [1]: /embed/inline-graphic-1.gif [2]: /embed/inline-graphic-2.gif

  • balestraite kli2vsi4o10o2 the first member of the Mica Group with octahedral v5
    American Mineralogist, 2015
    Co-Authors: Giovanni Orazio Lepore, Luca Bindi, Alberto Zanetti, Marco E Ciriotti, Olaf Medenbach, Paola Bonazzi
    Abstract:

    A Mica-Group mineral characterized by a high V content and free of Al was found in the manganesiferous beds within the metacherts of the ophiolitic sequences at the Cerchiara mine, Eastern Liguria (Italy), in association with hematite, quartz, and calcite. CheMical and structural characterization supported by Raman data defines this phase as a new mineral species, which is named balestraite after Corrado Balestra, a prominent Italian amateur mineralogist. Balestraite, ideally KLi2V5+Si4O10O2, is a 1 M trioctahedral Mica crystallizing in the C 2 space Group, with a = 5.2024(5), b = 8.9782(7), c = 9.997(2) A, β = 100.40(2)°, V = 459.3(1) A3, Z = 2. The reduction of symmetry from the “ideal” space Group C 2/ m is related to the ordering of V at only one of the two pseudo-symmetric octahedral sites. Vanadium forms very distorted octahedra with a [2+2+2] geometry characteristic of the valence state +5. The Li,V composition of the octahedral sheet, the pure tetrasilicic character of the tetrahedral sheet, and the anhydrous character produce unusual geometrical features for this Mica. The occurrence of 5+ as the dominant valence state of V and the virtually complete O2− → OH− substitution at the O4 site indicate strongly oxidizing conditions of crystallization, which are consistent with balestraite occurring at the boundary between carbonate-bearing veins and hematite bands. The new mineral and name were approved by the Commission on New Minerals, Nomenclature and Classification, IMA (2013-080).

Luca Bindi - One of the best experts on this subject based on the ideXlab platform.

  • a multimethodic approach for the characterization of manganiceladonite a new member of the celadonite family from cerchiara mine eastern liguria italy
    Mineralogical Magazine, 2017
    Co-Authors: Giovanni Orazio Lepore, Luca Bindi, F Di Benedetto, Enrico Mugnaioli, Cecilia Viti, Alberto Zanetti, Marco E Ciriotti, Paola Bonazzi
    Abstract:

    In the manganesiferous ores associated with the metacherts of the ophiolitic sequences at the Cerchiara mine, Eastern Liguria (Italy), a new Mn-bearing mineral belonging to the Mica Group has been recently found and characterized. High resolution transmission electron microscopy and electron diffraction tomography studies confirm that the mineral belongs to the Mica Group. Unit-cell parameters from the powder diffraction pattern are: a = 5.149(1), b = 8.915(1), c = 10.304(1) A, β = 102.03(1)°, space Group C 2 or C 2/ m . On the basis of the electron paramagnetic resonance spectroscopic results, the Mn4+ content represents a very subordinate fraction of the total Mn, the remaining occurring as Mn3+. The Raman spectrum clearly indicates the presence of OH Groups in the structure. Laser-ablation inductively-coupled-plasma mass-spectrometry measurements assess the presence of considerable amounts of Li. Assuming all Mn as Mn3+ and 22 negative charges, the empirical formula can be expressed as: (K0.83□0.17)(![Graphic][1] Mg0.80Li0.20![Graphic][2] )(Si3.89Al0.10)O10[(OH)1.92F0.08] with the sum of the octahedral cations indicating a ‘transitional’ character between a di- and a tri-octahedral structure. This formula corresponds ideally to the Mn3+ analogue of celadonite, thus expanding the range of solid solution in the celadonite family. The ideal end-member formula KMn3+MgSi4O10(OH)2 can be easily related to celadonite by the homovalent substitution VIMn3+ → VIFe3+. The mineral and its name have been approved by the Commission on New Minerals, Nomenclature and Classification of the International Mineralogical Association, (IMA 2015-052). [1]: /embed/inline-graphic-1.gif [2]: /embed/inline-graphic-2.gif

  • balestraite kli2vsi4o10o2 the first member of the Mica Group with octahedral v5
    American Mineralogist, 2015
    Co-Authors: Giovanni Orazio Lepore, Luca Bindi, Alberto Zanetti, Marco E Ciriotti, Olaf Medenbach, Paola Bonazzi
    Abstract:

    A Mica-Group mineral characterized by a high V content and free of Al was found in the manganesiferous beds within the metacherts of the ophiolitic sequences at the Cerchiara mine, Eastern Liguria (Italy), in association with hematite, quartz, and calcite. CheMical and structural characterization supported by Raman data defines this phase as a new mineral species, which is named balestraite after Corrado Balestra, a prominent Italian amateur mineralogist. Balestraite, ideally KLi2V5+Si4O10O2, is a 1 M trioctahedral Mica crystallizing in the C 2 space Group, with a = 5.2024(5), b = 8.9782(7), c = 9.997(2) A, β = 100.40(2)°, V = 459.3(1) A3, Z = 2. The reduction of symmetry from the “ideal” space Group C 2/ m is related to the ordering of V at only one of the two pseudo-symmetric octahedral sites. Vanadium forms very distorted octahedra with a [2+2+2] geometry characteristic of the valence state +5. The Li,V composition of the octahedral sheet, the pure tetrasilicic character of the tetrahedral sheet, and the anhydrous character produce unusual geometrical features for this Mica. The occurrence of 5+ as the dominant valence state of V and the virtually complete O2− → OH− substitution at the O4 site indicate strongly oxidizing conditions of crystallization, which are consistent with balestraite occurring at the boundary between carbonate-bearing veins and hematite bands. The new mineral and name were approved by the Commission on New Minerals, Nomenclature and Classification, IMA (2013-080).