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As-bearing new mineral species from Valletta mine, Maira Valley, Piedmont, Italy: II. Braccoite, NaMn2+5 [Si5AsO17(OH)](OH), description and crystal structure

Published online by Cambridge University Press:  02 January 2018

Fernando Cámara ,
Erica Bittarello ,
Marco E. Ciriotti ,
Fabrizio Nestola ,
Francesco Radica  and
Marco Marchesini
Fernando Cámara*
Affiliation:
Dipartimento di Scienze della Terra, Universita` degli Studi di Torino, via Tommaso Valperga Caluso 35, I-10125 Turin, Italy CrisDi, Interdepartmental Center for Crystallography, via Pietro Giuria 7, I-10125, Turin, Italy
Erica Bittarello
Affiliation:
Dipartimento di Scienze della Terra, Universita` degli Studi di Torino, via Tommaso Valperga Caluso 35, I-10125 Turin, Italy CrisDi, Interdepartmental Center for Crystallography, via Pietro Giuria 7, I-10125, Turin, Italy
Marco E. Ciriotti
Affiliation:
Associazione Micromineralogica Italiana, via San Pietro 55, I-10073 Devesi-Cirie´, Turin, Italy
Fabrizio Nestola
Affiliation:
Dipartimento di Geoscienze, Universita` degli Studi di Padova, via Giovanni Gradenigo 6, I-35131 Padova, Italy
Francesco Radica
Affiliation:
Dipartimento di Scienze Geologiche, Universita` degli Studi Roma Tre, largo San Leonardo Murialdo 1, I-00146 Rome, Italy
Marco Marchesini
Affiliation:
EEEP house, UNIR, Basing View, Basingstoke, Hampshire RG21 4YY, UK
*
* E-mail: [email protected]
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Abstract

The new mineral species braccoite, ideally NaMn2+5[Si5AsO17(OH)](OH), has been discovered in the Valletta mine dumps, in Maira Valley, Cuneo province, Piedmont, Italy. Its origin is probably related to the reaction between ore minerals and hydrothermal fluids. It occurs as subhedral crystals in brown-red coloured thin masses, with a pale-yellow streak and vitreous to resinous lustre. Braccoite is associated with tiragalloite, for which new data are provided, as well as gamagarite, hematite, manganberzeliite, palenzonaite, quartz, saneroite, tokyoite, unidentified Mn oxides, organic compounds, and Mn arsenates and silicates under study.

Braccoite is biaxial positive with refractive indices α = 1.749(1), β = 1.750(1), γ = 1.760(1). It is triclinic, space group P1̄, with a = 9.7354(4), b = 9.9572(3), c = 9.0657(3) Å, α = 92.691(2), β = 117.057(4), γ = 105.323(3)°, V = 740.37(4) Å3 and Z = 2. Its calculated density is 3.56 g/cm3. The ten strongest diffraction lines of the observed powder X-ray diffraction (XRD) pattern are [d in Å, (I), (hkl)]: 3.055 (69)(22̄1), 3.042 (43)(102), 3.012 (65)(32̄1̄), 2.985 (55)(23̄1̄), 2.825 (100)(213̄), 2.708 (92)(220), 2.627 (43)(23̄2̄), 2.381 (58)(41̄1̄), 2.226 (25)(214̄) and 1.680 (433̄)(36). Chemical analyses by wavelength-dispersive spectroscopy electron microprobe gave (wt.%): Na2O 4.06, CaO 0.05, MnO 41.76, MgO 0.96, Al2O3 0.04, CuO 0.02, SiO239.73, As2O5 6.87, V2O5 1.43, SO3 0.01 and F 0.04. H2O 2.20 was calculated on the basis of 2OH groups p.f.u. Raman spectroscopy confirmed the presence of (SiO4)4–, (AsO4)3– and OH groups. The empirical formula, calculated on the basis of Σ cations-(Na,K) = 11 p.f.u., in agreement with the results of the crystal structure, is Na1.06(Mn2+4.46Mn3+0.32Mg0.19V3+0.01Al0.01Ca0.01)[Si5(As0.48Si0.37V5+0.15)O17(OH)](OH0.98F0.02); the simplified formula is Na(Mn,Mg,Al,Ca)5[Si5(As,V,Si)O17(OH)](OH,F).

Single-crystal XRD allowed the structure to be solved by direct methods and revealed that braccoite is the As-dominant analogue of saneroite. The structure model was refined on the basis of 4389 observed reflections to R1 = 3.47%. Braccoite is named in honour of Dr Roberto Bracco (b. 1959), a systematic minerals collector with a special interest in manganese minerals. The new mineral was approved by the International Mineralogical Association Commission on New Minerals, Nomenclature and Classification (IMA 2013-093).

Keywords

braccoitesaneroitearseno-silicatestiragalloitenew mineral speciescrystal structureRamanVallettaPiedmontItaly
Type
Research Article
Information
Mineralogical Magazine , Volume 79 , Issue 1 , February 2015 , pp. 171 - 189
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2015

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References

Albee, A. and Chodos, A.A. (1970) Semiquantitative electron microprobe determination of Fe2+/Fe3+ and Mn2+/Mn3+ in oxides and silicates and its application to petrologic problems. American Mineralogist 55, 491-501.Google Scholar
Albrecht, J. (1990) An As-rich manganiferous mineral assemblage from the Ködnitz Valley (Eastern Alps, Austria): geology, mineralogy, genetic considerations, and implications for metamorphic Mn deposits. Neues Jahrbuch für Mineralogie, Monatshefte, 363-375.Google Scholar
Antofilli, M., Borgo, E. and Palenzona, A. (1983) I nostri minerali. Geologia e mineralogia in Liguria. SAGEP Editrice, Genova, 296 pp.Google Scholar
Barresi, A.A., Kolitsch, U., Ciriotti, M.E., Ambrino, P., Bracco, R. and Bonacina, E. (2005) La miniera di manganese di Varenche (Aosta, Italia nord-occidentale): ardennite, arseniopleite, manganberzeliite, pirofanite, sarkinite, thortveitite, nuovo As-Scanalogo della metavariscite e altre specie. Micro 3, 81-122.Google Scholar
Basso, R. and Della Giusta, A. (1980) The crystal structure of a new manganese silicate. Neues Jahrbuch für Mineralogie, Abhandlungen 138, 333-342.Google Scholar
Borgo, E. and Palenzona, A. (1988) I nostri minerali. Geologia e mineralogia in Liguria. Aggiornamento. SAGEP Editrice, Genova, 48 pp.Google Scholar
Bracco, R. and Balestra, C. (2014) La miniera di Monte Nero, Rocchetta Vara, La Spezia, Liguria: minerali classici e novità. Micro 12, 2-28.Google Scholar
Bracco, R., Callegari, A., Boiocchi, M., Balestra, C., Armellino, G. and Ciriotti, M.E. (2006) Costa Balzi Rossi (Magliolo, Val Maremola, Savona, Liguria): una nuova località per minerali di Terre Rare e scandio. Micro 4, 161-178.Google Scholar
Bracco, R., Balestra, C., Castellaro, F., Mills, S.J., Ma, C., Callegari, A.M., Boiocchi, M., Bersani, D., Cadoni, M. and Ciriotti, M.E. (2012) Nuovi minerali di Terre Rare da Costa Balzi Rossi, Magliolo (SV), Liguria. Micro 10, 66-77.Google Scholar
Brown, I.D. (1981) The bond-valence method: an empirical approach to chemical structure and bonding. Pp. 1-30. in: Structure and Bonding in Crystals II (M. O’Keeffe and A. Navrotsky, editors). Academic Press, New York.Google Scholar
Brugger, J., Krivovichev, S., Meisser, N., Ansermet, S. and Armbruster, T. (2006) Scheuchzerite, Na(Mn,Mg)9[VSi9O28(OH)](OH)3, a new singlechain silicate. American Mineralogist 91, 937-943.CrossRefGoogle Scholar
Cámara, F., Ciriotti, M.E., Bittarello, E., Nestola, F., Massimi, F., Radica, F., Costa, E., Benna, P. and Piccoli, G.C. (2014) As-bearing new mineral species from Valletta mine, Maira Valley, Piedmont, Italy: I. Grandaite, Sr2Al(AsO4)2(OH), description and crystal structure. Mineralogical Magazine 78, 757-774.CrossRefGoogle Scholar
Chen, Y.L., Huang, C.H. and Hu, W.P. (2005) Theoretical study of the small clusters of LiH, NaH, BeH2, and MgH2 . The Journal of Physical Chemistry A 109, 9627-9636.CrossRefGoogle Scholar
Downs, R.T. (2006) The RRUFF Project: an integrated study of the chemistry, crystallography, Raman and infrared spectroscopy of minerals. Program and Abstracts of the 19th General Meeting of the International Mineralogical Association in Kobe, Japan, O03-13.Google Scholar
Franks, F. (editor) (1973) Water: a Comprehensive Treatise, Vol. 2. Plenum, New York, 684 pp.Google Scholar
Gramaccioli, C.M., Griffin, W.L. and Mottana, A. (1980) Tiragalloite, Mn4[AsSi3O12(OH)], a new mineral and the first example of arsenatotrisilicate. American Mineralogist 65, 947-952.Google Scholar
Hammer, V.M.F., Libowitzky, E. and Rossman, G.R. (1998) Single crystal IR spectroscopy of very strong hydrogen bonds in pectolite, NaCa2[Si3O8(OH)], and serandi t e , NaMn2[Si3O8(OH)]. American Mineralogist 83, 569-576.CrossRefGoogle Scholar
Haring, M.M.M. and McDonald, A.M. (2014) Steedeite, NaMn2[Si3BO9](OH)2: characterization, crystalstructure determination, and origin. The Canadian Mineralogist 52, 47-60.CrossRefGoogle Scholar
Hatert, F., Mills, S.J., Pasero, M. and Williams, P.A. (2013) CNMNC guidelines for the use of suffixes and prefixes in mineral nomenclature, and for the preservation of historical names. European Journal of Mineralogy 25, 113-115.CrossRefGoogle Scholar
Hawthorne, F.C., Abdu, Y.A., Ball, N.A.and Pinch, W.W. (2013) Carlfrancisite: Mn 2+ 3 (Mn 2+ ,Mg,Fe 3+ , Al)42 (As 3+ O3)2 (As5+O4)4 [(Si ,As5+ +)O4]6 [(As5+,Si)O4]2(OH)42, a new arseno-silicate mineral from the Kombat mine, Otavi Valley, Namibia. American Mineralogist 98, 1693-1696.CrossRefGoogle Scholar
Yvon, Horiba Jobin (2004, 2005) LabSpec software for Raman spectroscopic data analysis, acquisition and manipulation. Version 5.64.15. HORIBA Jobin Yvon SAS, Villeneuve d’Ascq, France.Google Scholar
Jacobsen, S.D., Smyth, J.R., Swope, R.J. and Sheldon, R.I. (2000) Two proton positions in the very strong hydrogen bond of serandite, NaMn2[Si3O8(OH)]. American Mineralogist 85, 745-752.CrossRefGoogle Scholar
Kimura, Y. and Akasaka, M. (1999) Estimation of Fe2+/ Fe3+ and Mn2+/Mn3+ ratios by electron probe micro analyzer. Journal of the Mineralogical Society of Japan 28, 159-166. [in Japanese with English abstract].CrossRefGoogle Scholar
Larson, A.C. and Von Dreele, R.B. (1994) General Structure Analysis System (GSAS). Los Alamos National Laboratory Report LAUR, 86-748. Los Alamos National Laboratory, New Mexico, USA.Google Scholar
Libowitzky, E. (1999) Correlation of OH stretching frequencies and O–H_O hydrogen bond lengths in minerals. Monatshefte für Chemie 130, 1047-1059.CrossRefGoogle Scholar
Lucchetti, G., Penco, A.M. and Rinaldi, R. (1981) Saneroite, a new natural hydrated Mn-silicate. Neues Jahrbuch für Mineralogie, Monatshefte, 161-168.Google Scholar
Mandarino, J.A. (1979) The Gladstone-Dale relationship. Part III. Some general applications. The Canadian Mineralogist 17, 71-76.Google Scholar
Mandarino, J.A. (1981) The Gladstone-Dale relationship. Part IV. The compatibility concept and its application. The Canadian Mineralogist 19, 441-450.Google Scholar
Marchesini, M. and Pagano, R. (2001) The Val Graveglia Manganese District, Liguria, Italy. Mineralogical Record 32, 349-379.Google Scholar
Mills, S.J., Frost, R.L., Kloprogge, J.T. and Weier, M.L. (2005) Raman spectroscopy of the mineral rhodonite. Spectrochimica Acta 62, 171-175.CrossRefGoogle ScholarPubMed
Momma, K. and Izumi, F. (2011) "VESTA 3" for threedimensional visualization of crystal, volumetric and morphology d a t a. Journ a l o f Appl i e d Crystallography 44, 1272-1276.CrossRefGoogle Scholar
Myneni, S.C.B., Traina, S.J., Waychunas, G.A. and Logan, T.J. (1998a) Experimental and theoretical vibrational spectroscopic evaluation of arsenate coordination in aqueous solutions and solids. Geochimica et Cosmochimica Acta 62, 3285-3300.CrossRefGoogle Scholar
Myneni, S.C.B., Traina, S.J., Waychunas, G.A. and Logan, T.J. (1998b) Vibrational spectroscopy of functional group chemistry and arsenate coordination in ettringite. Geochimica et Cosmochimica Acta 62, 3499-3514.CrossRefGoogle Scholar
Nagashima, M. and Armbruster, T. (2010a) Saneroite: chemical and structural variations of manganese pyroxenoids with hydrogen bonding in the silicate chain. European Journal of Mineralogy 22, 393-402.CrossRefGoogle Scholar
Nagashima, M. and Armbruster, T. (2010b) Ardennite, tiragalloite and medaite: structural control of (As5+,V5+,Si4+)O4 tetrahedra in silicates. Mineralogical Magazine 74, 55-71.CrossRefGoogle Scholar
Nakamoto, K. (1986) Infrared and Raman Spectra of Inorganic and Coordination Compounds. Wiley, New York, 419 pp.Google Scholar
Nickel, E.H. and Grice, J.D. (1998) The IMA Commission on New Minerals and Mineral Names: procedures and guidelines on mineral nomenclature, 1998. The Canadian Mineralogist 36, 913-926.Google Scholar
Palenzona, A. (1991) I nostri minerali. Geologia e mineralogia in Liguria. Aggiornamento 1990, p. 48. Amici Mineralogisti Fiorentini, Associazione Piemontese Mineralogia Paleontologia & Mostra Torinese Minerali, Centro Mineralogico Varesino, Gruppo Mineralogico “A. Negro” Coop Liguria (GE), Gruppo Mineralogico Lombardo, Gruppo Mineralogico Paleontologico “3M”, SAGEP, Genoa, Italy [p. 48].Google Scholar
Palenzona, A. (1996) I nostri minerali. Geologia e mineralogia in Liguria, Aggiornamento 1995. Rivista Mineralogica Italiana 2, 149-172.Google Scholar
Palenzona, A., Martinelli, A., Bracco, R. and Balestra, C. (2006) IMA 2004-044 (scheuchzerite) alla miniera di Gambatesa. Prie 2, 11-12.Google Scholar
Pouchou, J.L. and Pichoir, F. (1984) A new model for quantitative analysis: Part I. Application to the analysis of homogeneous samples. La Recherche Aerospatiale 3, 13-38.Google Scholar
Pouchou, J.L. and Pichoir, F. (1985) ‘PAP’ j(rZ) procedure for improved quantitative microanalysis. Pp. 104-106. in: Microbeam Analysis. (J.T. Armstrong, Editor). San Francisco Press, San Francisco, USA.Google Scholar
Robinson, K., Gibbs, G.V. and Ribbe, P.H. (1971) Quadratic elongation: a quantitative measure of distortion in coordination polyhedra. Science 172, 567-570.CrossRefGoogle ScholarPubMed
Roth, P. (2007) Scheuchzerite. Pp.130–131. in: Minerals First Discovered in Switzerland and Minerals Named after Swiss Individuals. Kristallografik Verlag, Achberg, Germany.Google Scholar
Shannon, R.D. (1976) Revised effective ionic radii and systematic studies of interatomie distances in halides and chaleogenides. Acta Crystalographica 32, 751-767.CrossRefGoogle Scholar
Sheldrick, G.M. (2008) A short history of SHELX. Acta Crystallographica, A64, 112-122.CrossRefGoogle Scholar
Strunz, H. and Nickel, E.H. (2001) Strunz Mineralogical Tables. Chemical Structural Mineral Classification System, 9th Edition. Schweizerbart, Stuttgart, 870 pp.Google Scholar
Wilson, A.J.C. (editor) (1992) International Tables for Crystallography. Volume C: Mathematical, Physical and Chemical Tables. Kluwer Academic Publishers, Dordrecht, The Netherlands.Google Scholar
Yvon, K., Jeitschko, W. and Parthé, E. (1977) LAZY PULVERIX, a computer program, for calculating Xray and neutron diffraction powder patterns. Journal of Applied Crystallography 10, 73-74.CrossRefGoogle Scholar
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