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oxo amphiboles

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Journal Article

Ferri-fluoro-leakeite: a second occurrence at Bratthagen (Norway), with new data on Zn partitioning and the oxo component in Na amphiboles

R. Oberti, M. Boiocchi, F. C. Hawthorne, R. Kristiansen
Published: 01 August 2014
Mineralogical Magazine (2014) 78 (4): 861–869.
DOI: https://doi.org/10.1180/minmag.2014.078.4.07
... quantification of the oxo component in Na amphiboles possible. The results of the SREF procedure were interpreted in light of the present knowledge of amphibole crystal chemistry ( Oberti et al. , 2007 b ). In particular, the refined < T (1)–O> distance shows that Al is present solely as a C cation...
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The effect of oxo-component on the high-pressure behavior of amphiboles

P. Comodi, T. Boffa Ballaran, P.F. Zanazzi, C. Capalbo, A. Zanetti, S. Nazzareni
Published: 01 July 2010
American Mineralogist (2010) 95 (7): 1042–1051.
DOI: https://doi.org/10.2138/am.2010.3429
...P. Comodi; T. Boffa Ballaran; P.F. Zanazzi; C. Capalbo; A. Zanetti; S. Nazzareni Abstract The role of the oxo-component on the compressibility of amphibole was studied by means of high-pressure in situ single-crystal X-ray diffraction on two natural kaersutite megacrysts (samples DL5 and FR12) from...
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LIST OF OXO-AMPHIBOLES

Published: 01 April 2010
TABLE 1. LIST OF OXO-AMPHIBOLES
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The high-temperature behaviour of riebeckite: expansivity, deprotonation, selective Fe oxidation and a novel cation disordering scheme for amphiboles

Roberta Oberti, Massimo Boiocchi, Michele Zema, Frank C. Hawthorne, Günther J. Redhammer, Umberto Susta, Giancarlo Della Ventura
Published: 01 May 2018
European Journal of Mineralogy (2018) 30 (3): 437–449.
DOI: https://doi.org/10.1127/ejm/2018/0030-2712
... by single-crystal XRD analysis of the unit-cell parameters, but starts at 623 K as indicated by Mössbauer spectroscopy on powders (and by changes in the cation distribution observed by structure refinement). FTIR analysis shows that a completely deprotonated oxo-amphibole is obtained after annealing at 893...
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The crystal chemistry of oxo-mangani-leakeite and mangano-mangani-ungarettiite from the Hoskins mine and their impossible solid-solution: An XRD and FTIR study

Roberta Oberti, Giancarlo Della Ventura, Massimo Boiocchi, Alberto Zanetti, Frank C. Hawthorne
Published: 01 June 2017
Mineralogical Magazine (2017) 81 (3): 707–722.
DOI: https://doi.org/10.1180/minmag.2016.080.124
... South Wales, Australia). Notwithstanding the low OH content, FTIR analysis of selected samples has provided considerable information on short-range order in these Mn 3+ -rich amphiboles, and shows that Li is associated with occupied A sites and is linked to the oxo-component at the O(3) site...
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Oxidation or cation re-arrangement? Distinct behavior of riebeckite at high temperature

Giancarlo Della Ventura, Günther J. Redhammer, Federico Galdenzi, Gennaro Ventruti, Umberto Susta, Roberta Oberti, Francesco Radica, Augusto Marcelli
Published: 03 January 2023
American Mineralogist (2023) 108 (1): 59–69.
DOI: https://doi.org/10.2138/am-2022-8073
... breakdown products of the oxo-amphibole include aegirine + cristobalite + hematite. Based on the relative intensity of the (310) Bragg reflection, the activation energy ( E a ) for the riebeckite to oxo-riebeckite transition is 166 ± 6 kJ/mol. Under vacuum conditions, no Fe oxidation is observed...
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Nomenclature of the amphibole supergroup

Frank C. Hawthorne, Roberta Oberti, George E. Harlow, Walter V. Maresch, Robert F. Martin, John C. Schumacher, Mark D. Welch
Published: 01 November 2012
American Mineralogist (2012) 97 (11-12): 2031–2048.
DOI: https://doi.org/10.2138/am.2012.4276
... compositional variability in the amphibole structure. The amphibole supergroup is divided into two groups according to the dominant W species: W (OH,F,Cl)-dominant amphiboles and W O-dominant amphiboles (oxo-amphiboles). Amphiboles with (OH, F, Cl) dominant at W are divided into eight subgroups according...
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Solid solution between potassic alkali amphiboles from the silica-rich Kvaløya lamproite, West Troms Basement Complex, northern Norway

Kåre Kullerud, Dmitry Zozulya, Muriel Erambert, Erling J. K. Ravna
Published: 01 December 2013
European Journal of Mineralogy (2013) 25 (6): 935–945.
DOI: https://doi.org/10.1127/0935-1221/2013/0025-2340
... the volatile-rich lamproite magma. Possibly, amphibole core (composition A and B), formed in equilibrium with the fluid phase during crystallization of the melt, while amphibole rim (composition C) formed during subsequent mineral-fluid reactions. Presence of hematite in the lamproite matrix in addition to oxo...
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Exploring the potential of Raman spectroscopy for crystallochemical analyses of complex hydrous silicates: I. Amphiboles

Lisa Leissner, Jochen Schlüter, Ingo Horn, Boriana Mihailova
Published: 01 November 2015
American Mineralogist (2015) 100 (11-12): 2682–2694.
DOI: https://doi.org/10.2138/am-2015-5323
... the intensity ratio η between the total Raman scattering generated by OH bond stretching and the Raman peak near 670 cm −1 generated by TO 4 -ring vibrations. A small value of η (<0.09) combined with the presence of strong Raman scattering near 750–780 cm −1 is indicative of oxo-amphiboles. Guidelines...
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Ferri-kaersutite, NaCa 2 (Mg 3 TiFe 3+ )(Si 6 Al 2 )O 22 O 2 , a new oxo-amphibole from Harrow Peaks, Northern Victoria Land, Antarctica

Silvia Gentili, Cristian Biagioni, Paola Comodi, Marco Pasero, Catherine McCammon, Costanza Bonadiman
Published: 01 February 2016
American Mineralogist (2016) 101 (2): 461–468.
DOI: https://doi.org/10.2138/am-2016-5204
...Silvia Gentili; Cristian Biagioni; Paola Comodi; Marco Pasero; Catherine McCammon; Costanza Bonadiman Abstract Ferri-kaersutite, ideally NaCa 2 (Mg 3 TiFe 3+ )(Si 6 Al 2 )O 22 O 2 , is a new oxo-amphibole from Harrow Peaks, Northern Victoria Land, Antarctica. It occurs as brown prismatic crystals...
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Potassic-jeanlouisite from Leucite Hill, Wyoming, USA, ideally K(NaCa)(Mg 4 Ti)Si 8 O 22 O 2 : the first species of oxo amphibole in the sodium–calcium subgroup

Roberta Oberti, Massimo Boiocchi, Frank C. Hawthorne, Giancarlo Della Ventura, Gunnar Färber
Published: 01 August 2019
Mineralogical Magazine (2019) 83 (4): 587–593.
DOI: https://doi.org/10.1180/mgm.2019.38
...Roberta Oberti; Massimo Boiocchi; Frank C. Hawthorne; Giancarlo Della Ventura; Gunnar Färber Abstract Potassic-jeanlouisite, ideally K(NaCa)(Mg 4 Ti)Si 8 O 22 O 2 , is the first characterised species of oxo amphibole related to the sodium–calcium group, and derives from potassic richterite via...
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Raman scattering (crystal-elongation direction ⊥ E i || E s ) of T ...

Published: 01 November 2015
Figure 11 Raman scattering (crystal-elongation direction ⊥ E i || E s ) of T Al-rich oxo-amphiboles (kaersutite S32 and S33) compared to the spectra of T Al-rich OH-dominant amphiboles (hornblende S16 and pargasite S17). Spectra are vertically offset for clarity. (Color online.)
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Diagnostic plot for the presence of C Li based on the results of structure...

Published: 01 October 2007
the line by an amount proportional to the C Li content. Oxo-amphiboles, where the loss of H occurred after crystallization via oxidation of Fe 2+ to Fe 3+ at the M (1) site, also plot slightly below the line (anti-order). This is an updated version of the plot first proposed by Hawthorne et al. (1994) .
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Plot of C Ti versus Total C (2Ti + R 3+ − R 1+ ) from the chosen formulat...

Published: 01 December 2008
” shown in Fig. 3 . To a first approximation, all compositions can be described in terms of solid solutions between potassic-magnesio-arfvedsonite, K Na 2 (Mg 4 Fe 3+ ) Si 8 O 22 (OH, F) 2 and two oxo-amphibole compositions, potassic-obertiite, K Na 2 (Mg 3 Fe 3+ Ti) Si 8 O 22 O 2
Journal Article

Oxo-mangani-leakeite from the Hoskins mine, New South Wales, Australia: occurrence and mineral description

Roberta Oberti, Massimo Boiocchi, Frank C. Hawthorne, Neil A. Ball, Paul M. Ashley
Published: 01 October 2016
Mineralogical Magazine (2016) 80 (6): 1013–1021.
DOI: https://doi.org/10.1180/minmag.2016.080.037
...Roberta Oberti; Massimo Boiocchi; Frank C. Hawthorne; Neil A. Ball; Paul M. Ashley Abstract Oxo-mangano-leakeite, a newly approved end-member of the amphibole supergroup (IMA-CNMNC 2015-035), has been found in a rock containing manganese silicate and oxide at the Hoskins Mine, a Mn deposit 3 km...
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Different mechanisms of ferric iron and oxo-component accommodation in the ...

Published: 03 January 2023
Figure 12. Different mechanisms of ferric iron and oxo-component accommodation in the amphibole structure. Ferric iron determined by synchrotron Mössbauer spectroscPopy from area on the grain where major element composition and water content was also determined. The oxo-component was calculated
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Schematic pressure vs. temperature diagram showing amphibole stability and ...

Published: 01 October 2007
Figure 25. Schematic pressure vs. temperature diagram showing amphibole stability and some factors possibly affecting the oxo component in calcic amphiboles from hydrous volcanic systems. Initial crystallization conditions control both the oxo component and the incorporation of C cations
Journal Article

Oxo-magnesio-hastingsite, NaCa 2 (Mg 2 Fe 3 3 + )(Al 2 Si 6 )O 22 O 2 , a new anhydrous amphibole from the Deeti volcanic cone, Gregory rift, northern Tanzania

A. N. Zaitsev, E. Yu. Avdontseva, S. N. Britvin, A. Demény, Z. Homonnay, T. E. Jeffries, J. Keller, V. G. Krivovichev, G. Markl, N. V. Platonova, O. I. Siidra, J. Spratt, T. Vennemann
Published: 01 August 2013
Mineralogical Magazine (2013) 77 (6): 2773–2792.
DOI: https://doi.org/10.1180/minmag.2013.077.6.06
... amphibole from the Deeti volcanic cone in the Gregory rift (northern Tanzania). The mineral occurs as megacrysts up to 12 cm in size in crystal-rich tuff. Oxo-magnesio-hastingsite is brown with a vitreous lustre and has a perfect {110} cleavage. The measured density is 3.19(1) g/cm 3 . Ferri-kaersutite...
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Solid solution between potassic-obertiite and potassic-fluoro-magnesio-arfvedsonite in a silica-rich lamproite from northeastern Mozambique

Peter Robinson, Arne Solli, Ane Engvik, Muriel Erambert, Bernard Bingen, Henrik Schiellerup, Fernando Njange
Published: 01 December 2008
European Journal of Mineralogy (2008) 20 (6): 1011–1018.
DOI: https://doi.org/10.1127/0935-1221/2008/0020-1874
...” shown in Fig. 3 . To a first approximation, all compositions can be described in terms of solid solutions between potassic-magnesio-arfvedsonite, K Na 2 (Mg 4 Fe 3+ ) Si 8 O 22 (OH, F) 2 and two oxo-amphibole compositions, potassic-obertiite, K Na 2 (Mg 3 Fe 3+ Ti) Si 8 O 22 O 2...
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Ti-RICH FLUORO-RICHTERITE FROM KARIÅSEN (NORWAY): THE OXO-COMPONENT AND THE USE OF Ti 4+ AS A PROXY

Roberta Oberti, Massimo Boiocchi, Frank C. Hawthorne, Fernando Cámara, Marco E. Ciriotti, Svein A. Berge
Published: 14 September 2015
The Canadian Mineralogist (2015) 53 (2): 285–294.
DOI: https://doi.org/10.3749/canmin.1400059
... Fe 3+ 0.01 Ti 4+ 0.32 ) T (Si 7.18 Al 0.82 )O 22 W [(OH) 0.58 O 0.27 F 1.15 ], found in pegmatitic veins at Kariåsen, Larvik Plutonic Complex, Norway, provides an excellent example of the detection and estimation of the oxo component in amphibole. The use of Ti as a proxy for the oxo component...
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