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Tvrdýite, Fe2+Fe32+Al3(PO4)4(OH)5(OH2)4·2H2O, a new phosphate mineral from Krásno near Horní Slavkov, Czech Republic

Published online by Cambridge University Press:  02 January 2018

J. Sejkora ,
I. E. Grey ,
A. R. Kampf ,
J. R. Price  and
J. Čejka
J. Sejkora*
Affiliation:
Department of Mineralogy and Petrology, National Museum, Cirkusová 1740, Praha 9, 193 00, Czech Republic
I. E. Grey
Affiliation:
CSIRO Mineral Resources, Private Bag 10, Clayton South, Victoria 3169, Australia
A. R. Kampf
Affiliation:
Mineral Sciences Department, Natural History Museum of Los Angeles County, 900 Exposition Boulevard, Los Angeles, CA 90007, USA
J. R. Price
Affiliation:
Australian Synchrotron, 800 Blackburn Road, Clayton, Victoria 3168, Australia
J. Čejka
Affiliation:
Department of Mineralogy and Petrology, National Museum, Cirkusová 1740, Praha 9, 193 00, Czech Republic
*
*E-mail: [email protected]
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Abstract

Tvrdýite, Fe2+Fe3+2A13(PO4)4(OH)5(OH2)4·2H2O, is a new phosphate mineral from the abandoned Huber open pit, in the Krásno ore district near Horní Slavkov, western Bohemia, Czech Republic. It was found along with Al-rich beraunite, fluorapatite and pharmacosiderite in a cavity of quartz gangue. Tvrdýite forms acicular to fibrous crystals with diameters in the range 0.5–5 μm and lengths up to 300 μm, partly grouped in radiating aggregates up to 3 mm in size. It has a silvery to olive, greyish green colour with pearly lustre, greyish-white streak and is very brittle with an uneven fracture; individual fibres are somewhat flexible. Cleavage on {100} is good; the Mohs hardness is ∼3–4. The calculated density is 2.834 g cm–3. Tvrdýite is optically biaxial (–), with α = 1.650(2), β = 1.671(1) and γ = 1.677(1) (white light); 2V = 56(1)°; dispersion: r > v, strong; optical orientation: Z = b, X ≈ a, Y ≈ c; pleochroism: X = greenish blue, Y = yellowish orange, Z = yellowish orange (X>> Y > Z). Tvrdýite is monoclinic, space group C2/c, a = 20.564(4), b = 5.101(1), c = 18.883(4) Å, β = 93.68(3)° and V = 1976.7(7) Å3, Z = 4, a:b:c= 4.031:1:3.702. The strongest eight lines in the powder X-ray diffraction (XRD) pattern [d in Å (I)(hkl)] are 10.227 (100) (200), 9.400 (6) (002), 7.156 (14) (202), 5.120 (7) (400), 3.416 (11) (600), 3.278 (6) (602), 2.562 (5) (800) and 2.0511 (3) (10,0,0). Chemical analyses by electron microprobe yielded MnO 0.01, ZnO 5.08, , FeO 4.31, Fe2O3 21.16, Al2O316.71, P2O5 32.64, As2O5 2.56, F 0.53, H2O (calc.) 17.84, O = F –0.22, total 100.62 wt.%. The resulting empirical formula, calculated on the base of 27 anions, obtained from the crystal structure, is Zn0.52Fe2+0.50Fe3+2.21Al2.75(PO4)3.86(AsO4)0.19OH4.60F0.23(OH2)4·2H2O. The ideal formula, Fe2+Fe3+2Al3(PO4)4(OH)5(OH2)4-2H2O, requires FeO 8.75, Fe2O3 19.44, Al2O3 18.62, P2O5 34.56, H2O 18.64, total 100.00 wt.%. The crystal structure of tvrdýite was solved from single-crystal data (synchrotron beamline) and refined to R1 = 0.038 for 2276 reflections with I > 2σ(I). Tvrdýite is isostructural with beraunite, but contains dominant Al in two of the four independent M sites, which are all occupied by Fe in beraunite.

Keywords

tvrdýitenew mineralphosphateberaunitecrystal structureKrásno near Horní SlavkovCzech Republic
Type
Research Article
Information
Mineralogical Magazine , Volume 80 , Issue 6 , October 2016 , pp. 1077 - 1088
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2016

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References

Anthony, J.W., Bideaux, R.A., Bladh, K.W. and Nichols, M.C. (2000) Handbook of Mineralogy, volume IV, Arsenates, Phosphates, Vanadates., Mineral Data Publishing, Tucson Arizona.Google Scholar
Beran, P. and Sejkora, J. (2006) The Krásno Sn-W ore district near Horní Slavkov: mining history, geological and mineralogical characteristics. Journal of the Czech Geological Society, 51, 3–42.Google Scholar
Breithaupt, A.,(1841) Vollständiges Handbuch der Mineralogie., Arnoldische Buchhandlung, Dresden und Leipzig, Volume p. 156.Google Scholar
Burnham, C.W., (1962) Lattice constant refinement. Carnegie Institute Washington Yearbook, 6, 132–135.Google Scholar
Chukanov, N.V. (2014) Infrared Spectra of Minerals, Extended Library., Springer, Dodrecht, The Netherlands.CrossRefGoogle Scholar
Fanfani, L. and Zanazzi, P.F. (1967) The crystal structure of beraunite. Acta Crystallographica, 22 173–181.Google Scholar
Frost, R.L., López, A., Scholz, R., Xi, Y and Lana, C. (2014) The molecular structure of the phosphate mineral beraunite Fe2þFe35þ(PO4)4(OH)5:4H2O.. Spectrochimica Acta Part A: Molecular and Biomolecular Spectroscopy, 128, 408–412.CrossRefGoogle Scholar
Gunter, M.E., Bandli, B.R., Bloss, F.D., Evans, S.H., Su, S.C. and Weaver, R. (2004) Results from a McCrone spindle stage short course, a new version of EXCALIBR, and how to build a spindle stage. The Microscope, 52, 23—39.Google Scholar
Libowitzky, E. (1999) Correlation of O-H stretching frequencies and 0H---0 hydrogen bond lengths in minerals. Monatshefte für Chemie, 130, 1047–1059.CrossRefGoogle Scholar
Lutz, H.D. (1995) Hydroxide ions in condensed materials — Correlation of spectroscopic and structural data. Structure and Bonding, 82, 86–103.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
Marzoni Fecia, di Cossato Y., Orlandi, P. and Pasero, M. (1989) Manganese-bearing beraunite from Mangualde, Portugal: mineral data and structure refinement. The Canadian Mineralogist, 27, 441–446.Google Scholar
Mills, S.J., Kolitsch, U., Birch, W.D. and Sejkora, J. (2008) Kunatite, CuFe-+(PO4)2(OH)2-4H2O, a new member of the whitmoreite group, from Lake Boga, Victoria, Australia. Australian Journal of Mineralogy, 14, 3–12.Google Scholar
Mills, S.J., Kampf, A.R., Sejkora, J., Adams, P.M., Birch, W.D. and Plášil, J. (2011) Iangreyite: anew secondary phosphate mineral closely related to perhamite. Mineralogical Magazine, 75, 327—336.CrossRefGoogle Scholar
Mills, S.J., Sejkora, J., Kampf, A.R., Grey, I.E., Bastow, T.J., Ball, N.A., Adams, P.M., Raudsepp, M. and Cooper, M.A. (2012) Krásnoite, the fluorophosphate analogue of perhamite, from the Huber open pit, Czech Republic and the Silver Coin mine, Nevada, USA. Mineralogical Magazine, 76, 625–634.CrossRefGoogle Scholar
Moore, P.B. (1970) Crystal chemistry of the basic iron phosphates. American Mineralogist, 55, 135–169.Google Scholar
Moore, P.B. and Kampf, A.R. (1992) Beraunite: refine-ment, comparative crystal chemistry, and selected bond valences. Zeitschrift fur Kristallographie, 201, 263–281.Google Scholar
Nakamoto, K. (1986) Infrared and Raman spectra of Inorganic and Coordination Compounds. John Wiley and Sons, New York.Google Scholar
Ondruš, P. (1993) A computer program for analysis of X-ray powder diffraction patterns. Materials Science Forum, EPDIC-2, Enchede, 133-136, 297–300.Google Scholar
Pažout, R., Sejkora, J., Maixner, J., Dušek, M. and Tvrdý, J. (2015) Refikite from Krásno, Czech Republic: a crystal and molecular-structure study. Mineralogical Magazine, 79, 59–70.CrossRefGoogle Scholar
Pechkovskii, Y.Y, Mel'nikova, R.Y.a., Dzyuba, E.D., Barannikova, T.I., Nikanovich, M.V. (1981) Atlas of Infrared Spectra of Phosphates. Orthophosphates. Nauka, Moscow.Google Scholar
Plášil, J. and Tvrdý, J. (2008) Uranopilite and jáchymovite from uranium deposit Horní Slavkov. Bulletin mineralogicko-petrologického oddelení Národního muzea v Praze, 16, 61—64.Google Scholar
Pouchou, J.L. and Pichoir, F. (1985) “PAP” (j ρZ) procedure for improved quantitative microanalysis. Pp. 104-106 in: Microbeam Analysis, (J.T. Armstrong, editor). San Francisco Press, San Francisco USA.Google Scholar
Sejkora, J. and Tvrdý, J. (2009) Seltene und neue Mineralien aus den Zinnlagerstätten des Erzreviers Horní Slavkov. Lapis, 34, 53—62.Google Scholar
Sejkora, J., Ondruš, P., Fikar, M., Veselovský F., Mach, Z., Gabašová, A., Škoda, R. and Beran, P. (2006a) Supergene minerals at the Huber stock and Schnöd stock deposits, Krásno ore district, the Slavkovský les area, Czech Republic. Journal of the Czech Geological Society, 51, 57–101.Google Scholar
Sejkora, J., Škoda, R. and Ondruš, P. (2006b) New naturally occurring mineral phases from the Krásno -Horní Slavkov area, western Bohemia, Czech Republic. Journal of the Czech Geological Society, 51, 159–187.Google Scholar
Sejkora, J, Škoda, R., Ondruš, P., Beran, P. and Süsser, C. (2006c) Mineralogy of phosphate accumulations in the Huber stock, Krásno ore district, Slavkovský les area, Czech Republic. Journal of the Czech Geological Society, 51, 103–147.Google Scholar
Sejkora, J., Bureš, B. and Tvrdy, I (2008) Nordstrandit von Depoltovice bei Karlovy Vary (Karlsbad), Tschechien. Lapis, 51, 36—38.Google Scholar
Sejkora, J., Plasil, I and Filip, I (2011) Plimerite from Krásno near Horní Slavkov ore district, Czech Republic. Journal ofGeosciences, 33, 215–229.Google Scholar
Sheldrick, G.M. (2008) A short history of SHELX. Acta Crystallographica, A64, 112—122.CrossRefGoogle Scholar
Tvrdý, J. and Plášil, J. (2010) Jáchymov — Reiche Erzlagerstätte und Radonbad im böhmischen Westerzgebirge. Aufschluss, 61, 277–292.Google Scholar
Yvon, K., Jeitschko, W. and Parthé, E. (1977) Lazy Pulverix, a computer program for calculation X-ray and neutron diffraction powder patterns. Journal of Applied Crystallography, 10, 73—74.CrossRefGoogle Scholar