Skip to main content Accessibility help

Arsenic-bearing new mineral species from Valletta mine, Maira Valley, Piedmont, Italy: I. Grandaite, Sr2Al(AsO4)2(OH), description and crystal structure

  • F. Cámara (a1) (a2), M. E. Ciriotti (a3), E. Bittarello (a1) (a2), F. Nestola (a4), F. Massimi (a5), F. Radica (a6), E. Costa (a1), P. Benna (a1) (a2) and G. C. Piccoli (a7)...


The new mineral species grandaite, ideally Sr2Al(AsO4)2(OH), has been discovered on the dump of Valletta mine, Maira Valley, Cuneo province, Piedmont, Italy. Its origin is related to the reaction between the ore minerals and hydrothermal solutions. It occurs in thin masses of bright orange to salmon to brown coloured crystals, or infrequently as fan-like aggregates of small (<1 mm) crystals, with reddish-brown streak and waxy to vitreous lustre. Grandaite is associated with aegirine, baryte, braunite, hematite, tilasite, quartz, unidentified Mn oxides and Mn silicates under study.

Grandaite is biaxial (+) with refractive indices α = 1.726(1), β = 1.731(1), γ = 1.752(1). Its calculated density is 4.378 g/cm3. Grandaite is monoclinic, space group P21/m, with a = 7.5764(5), b = 5.9507(4), c = 8.8050(6) Å, β = 112.551(2)°, V = 366.62(4) Å3 and Z = 2. The eight strongest diffraction lines of the observed X-ray powder diffraction pattern are [d in Å, (I), (hkl)]: 3.194 (100)(11), 2.981 (50.9)(020), 2.922 (40.2)(03), 2.743 (31.4)(120), 2.705 (65.2)(112), 2.087 (51.8) (23), 1.685 (24.5)(321), 1.663 (27.7)(132). Chemical analyses by electron microprobe gave (wt.%) SrO 29.81, CaO 7.28, BaO 1.56, Al2O3 7.07, Fe2O3 2.34, Mn2O3 1.88, MgO 1.04, PbO 0.43, As2O5 44.95, V2O5 0.50, P2O5 0.09, sum 96.95; H2O 1.83 wt.% was calculated by stoichiometry from the results of the crystal-structure analysis. Raman and infrared spectroscopies confirmed the presence of (AsO4)3− and OH groups. The empirical formula calculated on the basis of 9 O a.p.f.u., in agreement with the structural results, is (Sr1.41Ca0.64Ba0.05Pb0.01)∑=2.11(Al0.68Fe0.14 3+Mn0.12 3+Mg0.13)∑=1.07 [(As0.96V0.01)∑=0.97O4]2(OH), the simplified formula is (Sr,Ca)2(Al,Fe3+)(AsO4)2(OH) and the ideal formula is Sr2Al(AsO4)2(OH).

The crystal structure was solved by direct methods and found to be topologically identical to that of arsenbrackebuschite. The structure model was refined on the basis of 1442 observed reflections to R 1 = 2.78%. In the structure of grandaite, chains of edge-sharing M 3+ octahedra run along [010] and share vertices with T5+ tetrahedra, building up [M 3+(T 5+O4)2(OH, H2O)] units, which are connected through interstitial divalent cations. Grandaite is named after the informal appellation of the province where the type locality is located. The new mineral was approved by the International Mineralogical Association Commission on New Minerals, Nomenclature and Classification (IMA2013-059). The discovery of grandaite and of other members of the group (description still in progress) opens up the possibility of exploring the crystal chemistry of the brackebuschite supergroup.


Corresponding author


Hide All
Abraham, K., Kautz, K., Tillmanns, E. and Walenta, K. (1978) Arsenbrackebuschite, Pb2(Fe,Zn)(OH,H2O) [AsO4]2, a new arsenate mineral. Neues Jahrbuch für Mineralogie, Monatshefte, 1978, 193196.
Antofilli, M., Borgo, E. and Palenzona, A. (1983) I nostri minerali. Geologia e mineralogia in Liguria. SAGEP Editrice, Genoa, Italy, 296 pp. [in Italian].
Basso, R., Palenzona, A. and Zefiro, L. (1987) Gamagarite: new occurrence and crystal structure refinement. Neues Jahrbuch für Mineralogie, Monatshefte, 1987, 295304.
Biagioni, C., Bonaccorsi, E., Cámara, F., Cadoni, M., Ciriotti, M.E., Bersani, D. and Kolitsch, U. (2013) Lusernaite-(Y), Y4Al(CO3)2(OH,F)11·6H2O, a new mineral species from Luserna Valley, Piedmont, Italy: Description and crystal structure. American Mineralogist, 98, 13221329.
Berzelius, J. (1818) Undersökning af ett hittills obemärkt Fossil, som stundom följer den Siberiska kromsyrade blyoxiden. Afhandlingar i Fysik, Kemi och Mineralogi, 6, 246254.[in Swedish].
Bideaux, R.A., Nichols, M.C. and Williams, S.A. (1966) The arsenate analog of tsumebite, a new mineral. American Mineralogist, 51, 258259.
Borgo, E. and Palenzona, A. (1988) I nostri minerali. Geologia e mineralogia in Liguria. Aggiornamento 1988. SAGEP Editrice, Genoa, Italy, 48 pp. [in Italian].
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.
Brugger, J. and Gieré, R. (1999) As, Sb, and Ce enrichment in minerals from a metamorphosed Fe- Mn deposit (Val Ferrera, Eastern Swiss Alps). The Canadian Mineralogist, 37, 3752.
Bruker AXS (2003) SAINT. Data Reduction Software, version 6.45A. Wisconsin, USA.
Brunet, F. and Chopin, C. (1995) Bearthite, Ca2Al(PO4)2OH: stability, thermodynamic properties and phase relations. Contributions to Mineralogy and Petrology, 121, 258266.
Busz, K. (1912) Tsumebit, ein neues Mineral von Otavi und Zinnsteinkristalle. Deutschen Naturforscher und Artze in Münster, 84, 230230.[in German].
Chopin, C., Brunet, F., Gebert, W., Medenbach, O. and Tillmanns, E. (1993) Bearthite, Ca2Al[PO4]2(OH), a new mineral from high-pressure terranes of the western Alps. Schweizerische Mineralogische und Petrographische Mitteilungen, 73, 19.
Christy, A.G., Grew, E.S., Mayo, S.C., Yates, M.G. and Belakovskiy, D.I. (1998) Hyalotekite, (Ba,Pb,K)4 (Ca,Y)2Si8(B,Be)2(Si,B)2O28F, a tectosilicate related to scapolite: new structure refinement, phase transitions and a short-range ordered 3b superstructure. Mineralogical Magazine, 62, 7792.
Clark, A.M., Criddle, A.J., Roberts, A.C., Bonardi, M. and Moffatt, E.A. (1997) Feinglosite, a new mineral related to brackebuschite, from Tsumeb, Namibia. Mineralogical Magazine, 61, 285289.
Cocco, G., Fanfani, L. and Zanazzi, P.F. (1967) The crystal structure of fornacite. Zeitschrift für Kristallographie, 124, 385397.
de Villiers, J.E. (1943) Gamagarite, a new vanadium mineral from the Postmasburg manganese deposits. American Mineralogist, 28, 329335.
Donaldson, D.M. and Barnes, W.H. (1955) The structures of the minerals of the descloizite group and adelite groups: III – brackebuschite. American Mineralogist, 40, 597613.
Emsley, J. (2011) Arsenic. Pp. 47–55 in: Nature’s Building Blocks: An A–Z Guide to the Elements. Oxford University Press, Oxford, UK.
Fanfani, L. and Zanazzi, P.F. (1967) Structural similarities of some secondary lead minerals. Mineralogical Magazine, 36, 522529.
Fanfani, L. and Zanazzi, P.F. (1968) The crystal structure of vauquelinite and the relationships to fornacite. Zeitschrift für Kristallographie, 126, 433443.
Foley, J.A., Hughes, J.M. and Lange, D. (1997) The atomic arrangement of brackebuschite, redefined as Pb2(Mn3+,Fe3+)(VO4)2(OH), and comments on Mn3+ octahedra. The Canadian Mineralogist, 35, 10271033.
Franchi, S. and Stella, A. (1930) Carta Geologica d’Italia 1:100. 000: Foglio 78–79 (Argentera- Dronero). 1a edizione. Regio Ufficio Geologico. Stabilimento Tipografico L. Salomone, Rome [in Italian].
Frost, R.L. and Keeffe, E.C. (2011) The mixed anion mineral parnauite Cu9[(OH)10|SO4|(AsO4)2]·7H2O – A Raman spectroscopic study. Spectrochimica Acta Part A, 81, 111116.
Geijer, P. (1921) The cerium minerals of Bastnäs at Riddarhyttan. Sveriges Geologiska Undersökning Årsbok, C304, 324.
Gidon, M., Kerchove, C., Michard, A., Tricart, P. and Goffé, B. (1994) Carte Géologique de la France à 1:50.000. Feuille Aiguille de Chambeyron (872). Notice Explicative. BRGM, Service Géologique National, Orléans, France [in French].
González del Tánago, J., La Iglesia, Á., Rius, J. and Fernández Santín, S. (2003) Calderó nite, a new leadiron- vanadate of the brackebuschite group. American Mineralogist, 88, 17031708.
Hak, J., Johan, Z., Kvaček, M. and Liebscher, W. (1969) Kemmlitzite, a new mineral of the woodhouseite group. Neues Jahrbuch für Mineralogie, Monatshefte, 1969, 201212.
Harlow, G.E., Dunn, P.J. and Rossman, G.R. (1984) Gamagarite: a re-examination and comparison with brackebuschite-like minerals. American Mineralogist, 69, 803806.
Hofmeister, W. and Tillmanns, E. (1978) Strukturelle untersuchungen an arsenbrackebuschit. Tschermaks Mineralogische und Petrographische Mitteilungen, 25, 153163.[in German].
Horiba Jobin, Yvon (2004, 2005) LabSpec software for Raman spectroscopic data analysis, acquisition and manipulation. Version 5.64.15. HORIBA Jobin Yvon SAS, Villeneuve d’Ascq, France.
Jonsson, O. (1970) The crystal structure of Na2Cr3O8OH and K2Cr3O8OH. Acta Chemica Scandinavica, 24, 36273644.
Kiat, J.M., Garnier, P., Calvarin, G. and Pinot, M. (1993) Structural study of lead orthophosphovanadates: role of the electron lone pairs in the phase transitions. Journal of Solid State Chemistry, 103, 490503.
Lacroix, A. (1915) Note préliminaire sur une nouvelle espèce minérale (furnacite), provenant du Moyen Congo (Afrique équatoriale française). Bulletin de la Société française de Minéralogie, 38, 198200.[in French].
Lacroix, A. (1916) Erratum concernant une nouvelle espèce minérale du Congo. Bulletin de la Société française de Minéralogie, 39, 8484.[in French].
LaForge, L. (1938) Crystallography of tsumebite. American Mineralogist, 23, 772782.
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.
Lefèvre, R. (1982) Les nappes briançonnaises internes et ultra-briançonnaises dans les Alpes Cottiennes méridionales. Thèse Scientifique, Université Paris Sud - Paris XI, Orsay, France [in French].
Libowitzky, E. (1999) Correlation of O–H stretching frequencies and O–H_O hydrogen bond lengths in minerals. Monatshefte für Chemie, 130, 10471059.
Mandarino, J.A. (1979) The Gladstone-Dale relationship. Part III. Some general applications. The Canadian Mineralogist, 17, 7176.
Mandarino, J.A. (1981) The Gladstone-Dale retationship. Part IV. The compatibility concept and its application. The Canadian Mineralogist, 19, 441450.
Mangione, T.G. (1999) Allume, vetriolo, ferro: attività minerarie e metallurgiche nel marchesato di Saluzzo (secoli XIV–XVI). Pp. 79–101 in: Miniere, fucine, metallurgia nel Piemonte medievale e moderno (R. Comba, editor). Società per gli Studi Storici Archeologici e Artistici della Provincia di Cuneo, Centro studi storico-etnografici, Museo provinciale "Augusto Doro", Rocca de’ Baldi, Cuneo, Italy [in Italian].
Matsubara, S., Miyawaki, R., Yokoyama, K., Shimizu, M. and Imai, H. (2004) Tokyoite, Ba2Mn3+(VO4)2(OH), a new mineral from the Shiromaru mine, Okutama, Tokyo, Japan. Journal of Mineralogical and Petrological Sciences, 99, 363367.
Medenbach, O., Abraham, K. and Gebert, W. (1983) Molybdofornacit, ein neues Blei–Kupfer–Arsenat– Molybdat–Hydroxid von Tsumeb, Namibia. Neues Jahrbuch für Mineralogie, Monatshefte, 1983, 289295.[in German].
Momma, K. and Izumi, F. (2011) VESTA 3 for threedimensional visualization of crystal, volumetric and morphology data. Journal of Applied Crystallography, 44, 12721276.
Moore, P.B., Irving, A.J. and Kampf, A.R. (1975) Foggite, CaAl(OH)2(H2O)[PO4]; goedkenite, (Sr,Ca)2Al(OH)[PO4 ] 2 ; and samuelsonite (Ca,Ba)Fe2+ 2 Mn2+ 2 Ca8Al2(OH)2[PO4]10: three new species from the Palermo No. 1 Pegmatite, North Groton, New Hampshire. American Mineralogist, 60, 957964.
Moore, P.B., Araki, T. and Ghose, S. (1982) Hyalotekite, a complex lead borosilicate: Its crystal structure and the lone-pair effect of Pb(II). American Mineralogist, 67, 10121020.
Moore, P.B., Sen Gupta, P.K. and Schlemper, E.O. (1985) Solid solution in plumbous potassium oxysilicate affected by interaction of a lone pair with bond pairs. Nature, 318, 548550.
Mukherjee, A., Sengupta, M.K. and Hossain, M.A. (2006) Arsenic contamination in groundwater: A global perspective with emphasis on the Asian scenario. Journal of Health Population and Nutrition, 24, 142163.
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, 32853300.
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, 34993514.
Nakamoto, K. (1986) Infrared and Raman Spectra of Inorganic and Coordination Compounds. Wiley, New York.
Nichols, M.C. (1966) The structure of tsumebite. American Mineralogist, 51, 267267.
Nickel, E.H. and Hitchen, G. (1994) The phosphate analog of molybdofornacite from Whim Creek, Western Australia. Mineralogical Record, 25, 203204.
Norman, N.C. (editor) (1998) Chemistry of arsenic, antimony and bismuth. Blackie Academic and Professional, London, 483 pp.
Palenzona, A. (1991) I nostri minerali. Geologia e mineralogia in Liguria. Aggiornamento 1990. 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 [in Italian].
Palenzona, A. (1996) I nostri minerali. Geologia e mineralogia in Liguria, Aggiornamento 1995. Rivista Mineralogica Italiana, 2, 149172.[in Italian].
Pekov, I.V. (2007) New minerals from former Soviet Union countries, 1998–2006: new minerals approved by the IMA Commission on New Minerals and Mineral Names. Mineralogical Almanac, 11, 951.
Pekov, I.V., Kleimenov, D.A., Chukanov, N.V., Yakubovich, O.V., Massa, W., Belakovskiy, D.I. and Pautov, L.A. (2002) Bushmakinite Pb2Al(PO4)(VO4)(OH), a new mineral of the brackebuschite group from oxidized zone of Berezovskoye gold deposit, the Middle Urals. Zapiski Vserossijskogo Mineralogicheskogo Obshchestva, 131, 6271.
Piccoli, G.C. (editor) (2002) Minerali delle Alpi Marittime e Cozie Provincia di Cuneo. Pp. 147–148 in: Amici del Museo “F. Eusebio”. Alba, Cuneo, Italy [in Italian].
Pipino, G. (2010) Documenti minerari degli stati sabaudi. Museo Storico dell’Oro Italiano, Tipografia Pesce, Ovada (Alessandria), Italy, 323 pp. [in Italian].
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, 1338.
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, California, USA.
Rammelsberg, C. (1880) Über die vanadinerze aus dem Staat Có rdoba in Argentinien. Zeitschrift der Deutschen Geologischen Gesellschaft, 32, 708713.[in German].
Robinson, K., Gibbs, G.V. and Ribbe, P.H. (1971) Quadratic elongation: a quantitative measure of distortion in coordination polyhedra. Science, 172, 567570.
Rosický, V. (1912) Preslit, ein neues Mineral von Tsumeb in Deutsch-Südwestafrika. Zeitschrift für Krystallographie und Mineralogie, 51, 521526.[in German].
Roth, P. (2007) Bearthite. Pp. 44–45 in: Minerals first discovered in Switzerland and minerals named after Swiss individuals. Kristallografik Verlag, Achberg, Germany.
Schlüter, J., Gebhard, G. and Wappler, G. (1994) Tsumebit oder Arsentsumebit aus Tsumeb? Lapis, 19(10), 3134 [in German].
Sheldrick, G.M. (2008) A short history of SHELX. Acta Crystallographica, A64, 112122.
Shen, J. and Moore, P.B. (1982) Törnebohmite, RE2Al(OH)[SiO4]2: crystal structure and genealogy of RE(III)Si(IV) $ Ca(II)P(V) isomorphisms. American Mineralogist, 67, 10211028.
Spek, A.L. (2009) Structure validation in chemical crystallography. Acta Crystallographica, D65, 148155.
Spencer, L.J. (1913) A (sixth) list of new mineral names. Mineralogical Magazine, 16, 352378.
Strunz, H. and Nickel, E.H. (2001) Strunz Mineralogical Tables. Chemical Structural Mineral Classification System, 9th Edition. Schweizerbart, Stuttgart, Germany, 870 pp.
Twarakavi, N.K.C. and Kaluarachchi, J.J. (2006) Arsenic in the shallow ground waters of conterminous United States: assessment, health risks, and costs for MCL compliance. Journal of American Water Resources Association, 42, 275294.
Vaughan, D.J. (2006) Arsenic. Elements, 2, 7175.
Vésignié, J.P.L. (1935) Présentation d’échantillons. Bulletin de la Société française de Minéralogie, 58, 45.[in French].
Walenta, K. and Dunn, P.J. (1984) Arsenogoyazit, ein neues mineral der crandallitgruppe aus dem Schwarzwald. Schweizerische Mineralogische und Petrographische Mitteilungen, 64, 1119.[in German].
Wherry, E.T. (1921) New minerals. American Mineralogist, 6, 118119.
Williams, S.A. (1973) Heyite, Pb5Fe2(VO4)2O4, a new mineral from Nevada. Mineralogical Magazine, 39, 6568.
Wilson, A.J.C. (editor) (1992) International Tables for Crystallography. Volume C: Mathematical, physical and chemical tables. Kluwer Academic Publishers, Dordrecht, The Netherlands.
Wojdyr, M. (2010) Fityk: a general-purpose peak fitting program. Journal of Applied Crystallography, 43, 11261128.
Yakubovich, O.V., Massa, W. and Pekov, I.V. (2002) Crystal structure of the new mineral bushmakinite, Pb2{(Al,Cu)[PO4][(V,Cr,P)O4](OH)}. Doklady Earth Sciences, 382, 100105.
Zubkova, N.V., Pushcharovsky, D.Y., Giester, G., Tillmanns, E., Pekov, I.V. and Kleimenov, D.A. (2002) The crystal structure of arsentsumebite, Pb2Cu[(As,S)O4]2(OH). Mineralogy and Petrology, 75, 7988.


Type Description Title
Supplementary materials

Cámara et al. supplementary material

 Unknown (26 KB)
26 KB
Supplementary materials

Cámara et al. supplementary material
Structure file

 Unknown (89 KB)
89 KB

Arsenic-bearing new mineral species from Valletta mine, Maira Valley, Piedmont, Italy: I. Grandaite, Sr2Al(AsO4)2(OH), description and crystal structure

  • F. Cámara (a1) (a2), M. E. Ciriotti (a3), E. Bittarello (a1) (a2), F. Nestola (a4), F. Massimi (a5), F. Radica (a6), E. Costa (a1), P. Benna (a1) (a2) and G. C. Piccoli (a7)...


Full text views

Total number of HTML views: 0
Total number of PDF views: 0 *
Loading metrics...

Abstract views

Total abstract views: 0 *
Loading metrics...

* Views captured on Cambridge Core between <date>. This data will be updated every 24 hours.

Usage data cannot currently be displayed