Hostname: page-component-586b7cd67f-t8hqh Total loading time: 0 Render date: 2024-11-29T01:16:16.111Z Has data issue: false hasContentIssue false

Gemmological investigation of a synthetic blue beryl: a multi-methodological study

Published online by Cambridge University Press:  05 July 2018

I. Adamo
Affiliation:
Dipartimento di Scienze della Terra, Universita' degli Studi di Milano, Italy
G. D. Gatta*
Affiliation:
Dipartimento di Scienze della Terra, Universita' degli Studi di Milano, Italy CNR-Istituto per la Dinamica dei Processi Ambientali, Milano, Italy
N. Rotiroti
Affiliation:
Dipartimento di Scienze della Terra, Universita' degli Studi di Milano, Italy CNR-Istituto per la Dinamica dei Processi Ambientali, Milano, Italy
V. Diella
Affiliation:
CNR-Istituto per la Dinamica dei Processi Ambientali, Milano, Italy
A. Pavese
Affiliation:
Dipartimento di Scienze della Terra, Universita' degli Studi di Milano, Italy CNR-Istituto per la Dinamica dei Processi Ambientali, Milano, Italy
*

Abstract

A multi-methodological investigation of a synthetic Cu/Fe-bearing blue beryl [IV(Be2.86Cu0.14)∑=3.00VI(Al1.83Fe3+0.14Mn2+0.03Mg0.03)∑=2.03IV(Si5.97Al0.03∑=6.00O18.(Li0.12Na0.04.0.40H2O)] has been performed by means of gemmological standard testing, electron microprobe chemical analyses, laser ablation inductively coupled plasma mass spectroscopy, thermo-gravimetric analyses, infrared spectroscopy and single-crystal X-ray diffraction in order to determine the gemmological properties, crystal structure and crystal-chemistry of this material. The increasing production of marketable hydrothermal synthetic beryls with 'exotic' colours and the small number of studies on the accurate location of chromophores in the crystal structure inspired this multi-methodological investigation. The X-ray structural refinements confirm that the space group of the Cu/Fe-bearing blue beryl is P6/mcc, with unit-cell parameters: 9.2483 ≤ a ≤ 9.2502 Å and 9.2184 ≤ c ≤ 9.2211 Å. The analysis of the difference Fourier maps of the electron density suggests that Cu is located at the tetrahedral site (Wyckoff 6fposition) along with Be, whereas Fe shares the octahedral site with Al (4c position). No evidence of extra-framework Cu/Fe-sites (i.e. channel sites) has been found. The Li is probably located at the extra-framework 2b site. Infrared spectra show that the H2O molecules are present with two configurations: one with the H···H vector oriented ‖[0001] and the other with H···H vector oriented ⊥[0001].

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2008

Access options

Get access to the full version of this content by using one of the access options below. (Log in options will check for institutional or personal access. Content may require purchase if you do not have access.)

References

Ames, R.D. and Rossman, G.R. (1984) The high-temperature behaviour of water and carbon dioxide in cordierite and beryl. American Mineralogist, 69, 319327.Google Scholar
Andersson, L.O. (2006) The position of H+ , Li+ and Na+ impurities in beryl. Physics and Chemistry of Minerals, 33, 403416.CrossRefGoogle Scholar
Artioli, G., Rinaldi, R., Stahl, K. and Zanazzi, P.F. (1993) Structure refinements of beryl by single-crystal neutron and X-ray diffraction. American Mineralogist, 78, 762768.Google Scholar
Artioli, G., Rinaldi, R., Wilson, C.C. and Zanazzi, P.F. (1995) Single-crystal pulsed neutron diffraction of a highly hydrous beryl. Ada Crystallographica, B51, 733737.Google Scholar
Aurisicchio, C Fioravanti, G., Grubessi, O. and Zanazzi, P.F. (1988) Reappraisal of the crystal chemistry of beryl. American Mineralogist, 73, 826837.Google Scholar
Aurisicchio, C Grubessi, O. and Zecchini, P. (1994) Infrared spectroscopy and crystal chemistry of the beryl group. The Canadian Mineralogist, 32, 5568.Google Scholar
Bragg, W.L. and West, J. (1926) The structure of beryl. Proceedings of the Royal Society, London, 3A, 691714.Google Scholar
Brown, G.E. Jr. and Mills, B.A. (1986) High-temperature structure and crystal chemistry of hydrous alkali-rich beryl from the Harding pegmatite, Taos County, New Mexico. American Mineralogist, 71, 547556.Google Scholar
Cerny, P., Anderson, A.J., Tomascak, P.B. and Chapman, R. (2003) Geochemical and morphological features of beryl from the Bikita granitic pegmatite, Zimbabwe. The Canadian Mineralogist, 41, 10031011.CrossRefGoogle Scholar
Charoy, B., de Donate, P., Barres, O. and Pinto-Coelho, C. (1996) Channel occupancy in alkali-poor beryl from Serra Branca (Goias, Brasil): spectroscopic characterization. American Mineralogist, 81, 395403.CrossRefGoogle Scholar
de Almeida Sampaio Filho, H., Sighinolfi, G. and Galli, E. (1973) Contribution to crystal chemistry of beryl. Contributions to Mineralogy and Petrology, 38, 279290.CrossRefGoogle Scholar
Evdokimova, O.A., Belokoneva, E.L., Artemenko, V.V., Dubovskaya, V.M. and Urusov, V.S. (1989) Location of impurity cations in synthetic Co- and Cu-containing beryls according to results of precision X-ray structural analysis, ESR and optical spectroscopy. Kristallografiya, 34, 723730.Google Scholar
Farmer, V.C. (1974) The Infrared Spectra of Minerals. Mineralogical Society, London.CrossRefGoogle Scholar
Ferraris, G., Prencipe, M. and Rossi, P. (1999) Stoppaniite, a new member of the beryl group: crystal structure and crystal-chemical implications.European Journal of Mineralogy, 10, 491496.CrossRefGoogle Scholar
Fleet, M.E. (1981) The structure of magnetite. Ada Crystallographica, B37, 917920.Google Scholar
Gatta, G.D., Nestola, F., Bromiley, G.D. and Mattauch, S. (2006) The real topological configuration of the extra-framework content in alkali-poor beryl: a multi-methodological study. American Mineralogist, 91, 2934.CrossRefGoogle Scholar
Gibbs, G.V., Breck, D.W. and Meagher, E.P. (1968) Structural refinement of hydrous and anhydrous beryl, A12(Be3 Si6)O18 and emerald, AloBesSiojg. Lithos, 1, 275285.CrossRefGoogle Scholar
Goldman, D.S., Rossman, G.R. and Parkin, K.M. (1978) Channel constituents in beryl. Physics and Chemistry of Minerals, 3, 225235.CrossRefGoogle Scholar
Hawthorne, F.C. and Cerny, P. (1977) The alkali-metal positions in Cs-Li beryl. The Canadian Mineralogist, 15,414421.Google Scholar
Hazen, R.M., Au, A.Y. and Finger, L.W. (1986) High-pressure crystal chemistry of beryl (Be3Al2Si6O18) and euclase (BeAlSiO4OH). American Mineralogist, 71, 977984.Google Scholar
Ismunandar, BJ.K. and Hunter, B.A. (1999) Phase transformation in CURI12O4: a powder neutron diffraction study. Materials Research Bulletin, 34, 135143.CrossRefGoogle Scholar
Koivula, J.I. and Kammerling, R.C. (1988) Gem News. Unusual synthetic beryls from the Soviet Union. Gems and Gemology, 24, 252.Google Scholar
Koivula, J.I., Tannous, M. and Schmetzer, K. (2000) Synthetic gem materials and simulants in the 1990s. Gems and Gemology, 36, 360379 CrossRefGoogle Scholar
Kolesov, B.A. and Geiger, C.A. (2000) The orientation and vibrational states of H2O in synthetic alkali-free beryl. Physics and Chemistry of Minerals, 27, 557564.CrossRefGoogle Scholar
Larson, A.C. (1970) Crystallographic Computing (Ahmed, F.R., Hall, S.R. and Huber, C.P., editors). Munksgaard, Copenhagen, pp. 291294.Google Scholar
Manier-Glavinaz, V., Couty, R. and Lagache, M. (1989) The removal of alkalis from beryl: structural adjustments. The Canadian Mineralogist, 27, 663671.Google Scholar
Mashkovtsev, R.I. and Smirnov, S.Z. (2004) The nature of channel constituents in hydrothermal synthetic emerald. Journal of'Gemmology, 29, 129141.CrossRefGoogle Scholar
Morosin, B. (1972) Structure and thermal expansion of beryl. Ada Crystallographica, B28, 18991903.Google Scholar
Nassau, K. (1990) Synthetic gem materials in the 1980s. Gems and Gemology, 26, 5063.CrossRefGoogle Scholar
Oxford Diffraction (2005) CrysAHs Software system, Version 1.170. Xcalibur CCD system. Oxford Diffraction Ltd. Google Scholar
Prencipe, M. (2002) Ab initio Hartree-Fock study and charge density analysis of beryl (Al4Be6Sii2O36). Physics and Chemistry of Minerals, 29, 552561.CrossRefGoogle Scholar
Sanders, I.S. and Doff, D.H. (1991) A blue sodic beryl from southeast Ireland. Mineralogical Magazine, 55, 167172.CrossRefGoogle Scholar
Schmetzer, K. (1989) Types of water in natural and synthetic emerald. Neues Jahrbuch fur Mineralogie Monatshefte, 1, 541551.Google Scholar
Schmetzer, K. and Kiefert, L. (1990) Water in beryl – a contribution to the separability of natural from synthetic emeralds by infrared spectroscopy. Journal of Gemmology, 22, 215223.CrossRefGoogle Scholar
Schmetzer, K., Schwarz, D., Bernhardt, H.-J. and Hager, T. (2006) A new type of Tairus hydrothermally- grown synthetic emerald, coloured by vanadium and copper. Journal of Gemmology, 30, 5974.CrossRefGoogle Scholar
Sheldrick, G.M. (1997) SHELX-97. Programs for crystal structure determination and refinement. University of Gottingen, Germany.Google Scholar
Sheriff, B.L., Grundy, D.H., Hartman, J.S., Hawthorne, F.C. and Cerny, P. (1991) The incorporation of alkalis in beryl: multi-nuclear MAS NMR and crystal structure study. The Canadian Mineralogist, 29, 271285.Google Scholar
Webster, R. (2006) Gems: Their Sources, Descriptions and Identification. 6th edition (M. O'Donoghue, editor). Butterworth-Heinemann, Oxford, UK.Google Scholar
Wilson, AJ.C. and Price, E. (Eds) (1999) International Tables for Crystallography C. Kluwer Academic Publishers, Dordrecht, The Netherlands.Google Scholar
Wood, D.L. and Nassau, K. (1967) Infrared spectra of foreign molecules in beryl. Journal of Chemical Physics, 42, 22202228.CrossRefGoogle Scholar
Wood, D.L. and Nassau, K. (1968) The characterization of beryl and emerald by visible and infrared absorption spectroscopy. American Mineralogist, 53, 777800.Google Scholar