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The origin of black colouration in onyx agate from Mali

Published online by Cambridge University Press:  05 July 2018

J. Götze ,
L. Nasdala ,
U. Kempe ,
E. Libowitzky ,
A. Rericha  and
T. Vennemann
J. Götze*
Affiliation:
TU Bergakademie Freiberg, Institute of Mineralogy, Brennhausgasse 14, D-09596 Freiberg, Germany
L. Nasdala
Affiliation:
Institute of Mineralogy and Crystallography, University of Vienna, Althanstr. 14, A-1090 Wien, Austria
U. Kempe
Affiliation:
TU Bergakademie Freiberg, Institute of Mineralogy, Brennhausgasse 14, D-09596 Freiberg, Germany
E. Libowitzky
Affiliation:
Institute of Mineralogy and Crystallography, University of Vienna, Althanstr. 14, A-1090 Wien, Austria
A. Rericha
Affiliation:
Alemannenstraβe 6, D-14612 Falkensee, Germany
T. Vennemann
Affiliation:
TU Bergakademie Freiberg, Institute of Mineralogy, Brennhausgasse 14, D-09596 Freiberg, Germany
*
*E-mail: goetze@mineral.tu-freiberg.de
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Abstract

Natural onyx agate from Mali was investigated in an integrated mineralogical and chemical study to reveal the origin of the unusual black colouration. Detailed studies by polarizing microscopy, scanning electron microscopy and micro-Raman spectroscopy showed that the colour of the dark bands is related to the incorporation of small particles of carbon (low-crystalline graphite) up to 200 nm in size into the cryptocrystalline silica matrix. The dark bands have carbon contents of 1.88 wt.%. The location of the graphite particles is closely related to the primary structural banding in the chalcedony. Cathodoluminescence data shows that the banding is interrupted by small fissures containing secondary hydrothermal quartz. The carbon isotope composition (δ13C value of –31.1±0.2‰) of the carbonaceous material points to an organic precursor. Both the direct hydrothermal formation of graphite from methane under elevated temperature and the graphitization of organic precursors by secondary hydrothermal or metamorphic overprint are possible explanations for the colour of the dark bands. The graphitization of organic precursors results in an intense electron spin resonance line at geff = 2.0026.

Keywords

agateonyxRaman spectroscopycathodoluminescencecarbon isotopesradiation damage
Type
Research Article
Information
Mineralogical Magazine , Volume 76 , Issue 1 , February 2012 , pp. 115 - 127
Copyright
Copyright © The Mineralogical Society of Great Britain and Ireland 2012

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References

Altschuler, S.A. and Kosyrew, B.M. (1963) Paramagnetische Elektronenresonanz. Teubner, B.G. Verlagsgesellschaft, Leipzig, Germany.Google Scholar
Bljumenfeld, L.A., Wojedowski, W.W. and Semjonow, A.G. (1966) Die Anwendung der paramagnetischen Elektronenresonanz in der Chemie. Akademische Verlagsgesellschaft Geest & Portig K.-G., Leipzig, Germany.Google Scholar
Botis, S.M., Nokhrin, S., Pan, Y., Xu, Y., Bonli, T. and Sopuck, V. (2005) Natural radiation-induced damage in quartz. Correlations between cathodoluminescence colors and paramagnetic defects. The Canadian Mineralogist, 43, 1565–1580.CrossRefGoogle Scholar
Bungarten, G. and Luckhardt, J. (2008) Reiz der Antike. Michael Imhof Verlag, Braunschweig, Germany.Google Scholar
Caby, R., Andreopoulos-Renaud, U. and Pin, C. (1989) Late Proterozoic arc-continent and continent-continent collision in the pan-African trans-Saharan belt of Mali. Canadian Journal of Earth Sciences, 26, 1636–1646.CrossRefGoogle Scholar
Ferrari, A.C. and Robertson, J. (2000) Interpretation of Raman spectra of disordered and amorphous carbon. Physical Reviews B, 61, 14095–14107.CrossRefGoogle Scholar
Götze, J. (2011) Agate-Fascination between legend and science. Pp. 19–133. in: Agate III (Zenz, J., editor). Bode Verlag GmbH, Haltern, Germany.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. Contributions to Mineralogy and Petrology, 133, 96–105.CrossRefGoogle Scholar
Götze, J., Plötze, M., Fuchs, H. and Habermann, D. (1999) Defect structure and luminescence behaviour of agate-results of electron paramagnetic resonance (EPR) and cathodoluminescence (CL) studies. Mineralogical Magazine, 63, 149–163.CrossRefGoogle Scholar
Götze, J., Plötze, M. and Habermann, D. (2001) Cathodoluminescence (CL) of quartz: origin, spectral characteristics and practical applications. Mineralogy and Petrology, 71, 225–250.Google Scholar
Götze, J., Müller, A., Polgári, M. and Pál-Molnár, E. (2011) Biosignaturen in Achat/Chalcedon-die Rolle von Mikroorganismen bei der Bildung von SiO2 . Mineralienwelt, 22, 90–96.Google Scholar
Handley, K.M., Campbell, K.A., Mountain, B.W. and Browne, P.R.L. (2005) Abiotic-biotic controls on the origin and development of spicular sinter: in situ growth experiments, Champagne Pool, Waiotapu, New Zealand. Geobiology, 3, 93–114.CrossRefGoogle Scholar
Heaney, P.J. (1993) A proposed mechanism for the growth of chalcedony. Contributions to Mineralogy and Petrology, 115, 66–74.CrossRefGoogle Scholar
Hedges, J.I., Cowie, G.L., Ertel, J.R., Barbour, R.J. and Hatcher, P.G. (1985) Degradation of carbohydrates and lignins in buried woods. Geochimica et Cosmochimica Acta, 49, 701–711.CrossRefGoogle Scholar
Henn, U., Häger, T. and Milisenda, C.C. (2010) Ein Beitrag zum Thema Onyx. Zeitschrift der Deutschen Gemmologischen Gesellschaft, 59, 83–90.Google Scholar
Hoefs, J. (1997) Stable isotope geochemistry. Fourth edition. Springer, Berlin, 201 pp. Hon, D.N.-S. (1983) Mechanochemical process in cotton cellulose fibre. Journal of Applied Polymer Science, 37, 461–481.Google Scholar
House, C.H., Schopf, J.W., McKeegan, K.D., Coath, C.D., Harrison, T.M. and Stetter, K.O. (2000) Carbon isotopic composition of individual Precambrian microfossils. Geology, 28, 707–710.2.0.CO;2>CrossRefGoogle ScholarPubMed
Jeckel, P. (2009) Mali. Pp. 502–503. in: Achate II (Zenz, J. editor). Bode Verlag GmbH, Haltern, Germany.Google Scholar
Kawashima, Y. and Katagiri, G. (1995) Fundamentals, overtones, and combinations in the Raman spectrum of graphite. Physical Reviews B, 52, 10053–10059.CrossRefGoogle ScholarPubMed
Konhauser, K. (2007) Introduction to Geomicrobiology. Blackwell, Oxford, UK, 425 pp.Google Scholar
Krickl, R., Nasdala, L., Götze, J., Grambole, D. and Wirth, R. (2008) Alteration of SiO2 caused by natural and artificial alpha-irradiation. European Journal of Mineralogy, 20, 517–522.CrossRefGoogle Scholar
Luque, F.J., Pasteris, J.D., Wopenka, B., Rodas, M. and Barrenechea, J.F. (1998) Natural fluid-deposited graphite: mineralogical characteristics and mechanisms of formation. American Journal of Science, 298, 471–498.CrossRefGoogle Scholar
Moxon, T. (2002) Agate: a study of ageing. European Journal of Mineralogy, 14, 1109–1118.CrossRefGoogle Scholar
Moxon, T. and Carpenter, M.A. (2009) Crystallite growth kinetics in nanocrystalline quartz (agate and chalcedony). Mineralogical Magazine, 73, 551–568.CrossRefGoogle Scholar
Moxon, T. and Rios, S. (2004) Moganite and water content as a function of age in agate: an XRD and thermogravimetric study. European Journal of Mineralogy, 4, 693–706.Google Scholar
Moxon, T., Nelson, D.R. and Zhang, M. (2006) Agate recrystallization: evidence from samples found in Archaean and Proterozoic host rocks, Western Australia. Australian Journal of Earth Sciences, 53, 235–248.CrossRefGoogle Scholar
Moxon, T., Reed, S.J.B. and Zhang, M. (2007) Metamorphic effects on agate found near the Shap granite, Cumbria, England: as demonstrated by petrography, X-ray diffraction and spectroscopic methods. Mineralogical Magazine, 71, 461–476.CrossRefGoogle Scholar
Neuser, R.D., Bruhn, F., Götze, J., Habermann, D. and Richter, D.K. (1995) Kathodolumineszenz: Methodik und Anwendung. Zentralblatt für Geologie und Paläontologie Teil I, 1995, 287–306.Google Scholar
Owen, M.R. (1988) Radiation-damage halos in quartz. Geology, 16, 529–532.2.3.CO;2>CrossRefGoogle Scholar
Parenteau, M.N. and Cady, S.L. (2010) Microbial biosignatures in iron-mineralized phototrophic mats at Chocolate Pots Hot Springs, Yellowstone National Park, United States. PALAIOS, 25, 97–111.CrossRefGoogle Scholar
Paris, O., Zollfrank, C. and Zickler, C. (2005) Decomposition and carbonisation of wood biopolymers-a microstructural study of softwood pyrolysis. Carbon, 43, 53–66.CrossRefGoogle Scholar
Pitcairn, I.K., Roberts, S., Teagle, D.A.H. and Craw, D. (2005) Detecting hydrothermal graphite deposition during metamorphism and gold mineralization. Journal of the Geological Society, London, 162, 429–432.CrossRefGoogle Scholar
Ramseyer, K., Baumann, J., Matter, A. and Mullis, J. (1988) Cathodoluminescence colours of alphaquartz. Mineralogical Magazine, 52, 669–677.CrossRefGoogle Scholar
Rao, P.S., Weil, J.A. and Williams, J.A.S. (1989) EPR investigation of carbonaceous natural quartz single crystals. The Canadian Mineralogist, 27, 219–224.Google Scholar
Reysenbach, A.-L. and Cady, S.L. (2001) Microbiology of ancient and modern hydrothermal systems. Trends in Microbiology, 9, 79–86.CrossRefGoogle ScholarPubMed
Rumble, D. and Hoering, T.C. (1986) Carbon isotope geochemistry of graphite vein deposits from New Hampshire U.S.A. Geochimica et Cosmochimica Acta, 50, 1239–1247.CrossRefGoogle Scholar
Stevens Kalceff, M.A. and Phillips, M.R. (1995) Cathodoluminescence microcharacterization of the defect structure of quartz. Physical Reviews B, 52, 3122–3134.CrossRefGoogle Scholar
Street-Perrott, F.A. and Barker, P.A. (2008) Biogenic silica: a neglected component of the coupled global continental biochemical cycles of carbon and silicon. Earth Surface Processes and Landforms, 33, 1436–1457.CrossRefGoogle Scholar
Taut, T., Kleeberg, R. and Bergmann, J. (1998) Seifert Software: the new Seifert Rietveld program BGMN and its application to quantitative phase analysis. Materials Structure, 5, 57–66.Google Scholar
Witke, K., Götze, J., Rößler, R., Dietrich, D. and Marx, G. (2004) Raman and cathodoluminescence spectroscopic investigations on Permian fossil wood from Chemnitz-a contribution to the study of the permineralization process. Spectrochimica Acta Part A, 60, 2947–2956.CrossRefGoogle Scholar