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Defect structure and luminescence behaviour of agate — results of electron paramagnetic resonance (EPR) and cathodoluminescence (CL) studies

Published online by Cambridge University Press:  05 July 2018

J. Götze
Affiliation:
Department of Mineralogy, Freiberg University of Mining and Technology, D-09596 Freiberg, Germany
M. Plötze
Affiliation:
Department of Mineralogy, Freiberg University of Mining and Technology, D-09596 Freiberg, Germany
H. Fuchs
Affiliation:
Department of Mineralogy, Freiberg University of Mining and Technology, D-09596 Freiberg, Germany
D. Habermann
Affiliation:
Department of Geology, Ruhr-University Bochum, D-44780 Bochum, Germany

Abstract

Samples of agate and quartz incrustations from different parent volcanic rocks of certain world-wide localities were investigated by EPR, CL and trace element analysis. In all agate samples the following paramagnetic centres were detected:, E′1, [AlO4]0 [FeO4/M+]0 and [GeO4/M+]0. Centres of the type [TiO4/Li+]0 and [TiO4/H+]0, which were detected in quartz of the parent volcanics, are absent in agate. Generally, the abundance of centres (silicon vacancy) and E′1 centres (oxygen vacancy) in agate is remarkably higher than in quartz. The high defect density in agates points to rapid growth of silica from a strongly supersaturated solution probably with a noncrystalline precursor.

CL microscopy reveals internal structures and zoning in agates and quartz incrustations which clearly differ from those discernible by conventional polarizing microscopy. The CL spectra of agates differ from those of quartz from crystalline rocks. At least three broad emission bands were detected in the CL spectra: a blue band of low intensity, a yellow band at about 580 nm, and an intense red band at 650 nm. The CL emission at 650 nm shows some relations to the hydroxyl or alkali content and the abundance of centres and E′1 centres. The emission intensity increases during electron bombardement due to the conversion of different precursors (e.g. ≡Si-O-H, ≡Si-O-Na groups) into hole centres. Another conspicuous feature in the CL spectra of agates is the existence of a yellow emission band centred at around 580 nm. The predominance of the yellow CL emission band and the high concentration of E′1 centres are typical for agates of acidic volcanics and are indicative of a close relationship between the two.

Type
Research Article
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 1999 

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References

Alonso, P.J., Halliburton, L.E., Kohnke, E.E. and Bossoli, R.B. (1983) X-ray induced luminescence in crystalline SiO2. J. Appl. Phys., 54, 5369–75.Google Scholar
Bershov, L.V., Krylova, M.D. and Speranskij, A.V. (1978) The electron hole centres O-Al and Ti3+ as indicator for temperature conditions during regional metamorphosis (in Russ.). Izv. Akad. Nauk SSSR, Ser. geol., 113-7.Google Scholar
Blankenburg, H.-J. (1988) Agate (in German). Dt. Verl. f. Grundstoffindustrie, Leipzig.Google Scholar
Flörke, O.W., Köhler-Herbertz, B., Langer, K. and Tönges, I. (1982) Water in microcrystalline quartz of volcanic origin: agates. Contrib. Mineral. Petrol., 80, 324–33.Google Scholar
Flörke, O.W., Graetsch, H., Martin, B., Röller, K. and Wirth, R. (1991) Nomenclature of micro- and non-crystalline silica minerals, based on structure and microstructure. Neues Jahrb. Mineral., Abh., 163, 1942.Google Scholar
Fuchs, H. and Götze, J. (1996) Origin of volcanic agate -evidence from cathodoluminescence, EPR and geochemical studies. Intern. Conf. CL Rel. Techn. Geosci. Geomat., Nancy, Abstracts, 4950.Google Scholar
Gorton, N.T., Walker, G. and Burley, S.D. (1996) Experimental analysis of the composite blue CL emission in quartz — is this related to aluminium content Intern. Conf. CL Rel. Techn. Geosc. Geomat., Nancy, Abstracts 5960.Google Scholar
Götze, J. (1996) Cathodoluminescence of quartz -Principle and application in geosciences (in German). Aufschluss, 47, 215–23.Google Scholar
Götze, J. and Lewis, R. (1994) Distribution of REE and trace elements in size and mineral fractions of high purity quartz sands. Chem. Geol., 114, 4357.Google Scholar
Götze, J. and Plötze, M. (1997) Investigation of trace-element distribution in detrital quartz by Electron Paramagnetic Resonance (EPR). Eur. J. Mineral., 9, 529–7.Google Scholar
Götze, J., Nasdala, L., Kleeberg, R. and Wenzel, M. (1998): Occurrence and distribution of 'moganite' in agate/chalcedony: A combined micro-Raman, Rietveld, and cathodoluminescence study. Contrib. Mineral. Petrol. (in press).10.1007/s004100050440Google Scholar
Graetsch, H. (1994) Structural characteristics of opaline and microcrystalline silica minerals. In: Silica. Reviews in Mineralogy, 29, 209–32.Google Scholar
Griffiths, J.H.E., Owen, J. and Ward, I.M. (1954) Paramagnetic resonance in neutron-irradiated diamond and smoky quartz. Nature, 173, 439–42.Google Scholar
Heany, P.J. and Davis, A.M. (1995) Observation and origin of self-organized textures in agates. Science, 269, 1562–5.Google Scholar
Heany, P.J., Veblen, D.R. and Post, J.E. (1994) Structural disparities between chalcedony and macrocrystalline quartz. Amer. Mineral., 79, 452–60.Google Scholar
Luff, B.J. and Townsend, P.D. (1990) Cathodoluminescence of synthetic quartz. J. Phys. Condens. Matter, 2, 8089–97.Google Scholar
Mackey, J.H. (1963) EPR study of impurity-related color centers in germanium-doped quartz. J. Chem. Phys., 39, 7483.Google Scholar
Mineeva, R.M., Bershov, L.V. and Petrov, I. (1991) EPR of surface associated Fe3+ in polycrystalline quartz (in Russ.). Dokl. Akad. Nauk SSSR, 321, 368–72.Google Scholar
Moiseev, B.M. (1985) Natural Radiation Processes in Minerals (in Russ.). Nedra, Moscow.Google Scholar
Nettar, D. and Villafranca, J.J. (1985) A program for EPR powder spectren simulation. J. Magn. Res., 64, 61.Google Scholar
Neuser, R.D., Bruhn, F., Götze, J., Habermann, D. and Richter, D.K. (1995) Cathodoluminecence: method and application (in German). Zbl. Geol. Paliiont. Teil I, 1/2, 287306.Google Scholar
Nuttall, R.H.D. and Weil, J.A. (1981) The magnetic properties of the oxygen-hole aluminium centers in crystalline SiO2. I. [AlO4]0 Canad. J. Phys., 59, 1696–707.Google Scholar
Pearny, B., Eberhardt, P., Ramseyer, K., Mullis, J. and Pankrath, R. (1992) Microdistribution of Al, Li and Na in alpha-quartz: Possible causes and correlation with short-lived cathodoluminescence. Amer. Mineral., 77, 534–44.Google Scholar
Plötze, M. (1995) Investigation of quartz, scheelite and fluorite from hydrothermal rare-metal deposits by EPR (in German). Diss. TU Bergakademie Freiberg, 141 pp.Google Scholar
Plötze, M., Wolf, D. and Krbetschek, M.R. (1998) Radiation dependence of EPR and TL-spectra of quartz. Phys. Chem. Minerals (submitted).Google Scholar
Rakov, L.T., Kuvshinova, K.A., Moiseev, B.M., Pleskova, M.A. and Kandinov, M.N. (1985) Typomorphic properties of Ti centres in quartz (in Russ.). Dokl. Akad. Nauk SSSR, 317, 181–5.Google Scholar
Ramseyer, K., Baumann, J., Matter, A. and Mullis, J. (1988) Cathodoluminescence colours of alpha-quartz. Mineral. Mag., 52, 669–77.Google Scholar
Rink, W.J., Rendell, H.., Marseglia, E.A., Luff, B.J. and Townsend, P.D. (1993) Thermoluminescence spectra of igneous quartz and hydrothermal vein quartz. Phys. Chem. Minerals, 20, 353–61.Google Scholar
Rinneberg, H.. and Weil, J.A. (1972) EPR studies of Ti3+-H+ centers in X-irradiated alpha-quartz. J. Chem. Phys., 56, 2019–28.Google Scholar
Schrön, W., Kaiser, G. and Bombach, G. (1983) Trace element analysis in geological samples by emission spectrography with semiautomatic evaluation (in German). Z ang. Geol., 11, 559–65.Google Scholar
Serebrennikov, A.I., Valter, A.A., Mashkovtsev, R.I. and Shcherbakova, M.Ya. (1982) The investigation of defects in shock-metamorphosed quartz. Phys. Chem. Minerals, 8, 153–7.Google Scholar
Siegel, G.H. and Marrone, M.J. (1981) Photoluminescence in as-drawn and irradiated silica optical fibers: An assessment of the role of nonbrid-ging oxygen defect centres. J. Non-Cryst. Solids, 45, 235–47.Google Scholar
Stegger, P. and Lehmann, G. (1989) The structures of three centers of trivalent iron in alpha-quartz. Phys.Chem. Minerals, 16, 401–7.Google Scholar
Stevens Kalceff, M.A. and Phillips, M.R. (1995) Cathodoluminescence microcharacterization of the defect structure of quartz. Phys. Rev., B52, 3122–34.Google Scholar
Strunz, H. and Tennyson, C. (1982) Mineralogical Tables. Akademie-Verl.-ges. Geest & Portig, Leipzig.Google Scholar
Weeks, R.A. (1956) Paramagnetic resonance of lattice defects in irradiated quartz, J. Appl. Phys., 27, 1376–81.Google Scholar
Weil, J.A. (1984) A review of electron spin spectroscopy and its application to the study of paramagnetic defects in crystalline quartz. Phys. Chem. Minerals, 10, 149–65.Google Scholar
Weil, J.A. (1993) A review of the EPR spectroscopy of the point defects in α-quartz: The decade 1982-1992. In Physics and Chemistry of SiO2 and the Si-SiO2 interface 2 (Helms, C.R. and Deal, B.E., eds). Plenum Press, New York, 131–44.Google Scholar
Wright, P.M., Weil, J.A., Buch, T. and Anderson, J.H. (1963) Titanium colour centers in rose quartz. Nature, 197, 246–8.Google Scholar