Identification of Chinese fresh-water pearls using MN2+ activated cathodoluminescence
- 69 Downloads
Fresh-water tissue graft-cultured pearls from China were investigated using hot cathode and cold cathode cathodoluminescence microscopes. Supplementary investigations were done using X-radiography, a Scanning Electron Microscope, an optical microscope, and an Atomic Force Microscope (AFM). The results were compared with those of natural fresh-water pearls from the Mississippi river.
Thin sections of fresh-water natural pearls from the Mississippi river could be distinguished from those of fresh-water tissue graft cultured pearls from China using a hot cathode cathodoluminescence microscope according to the distribution of Mn2+ as follows: (1) Fresh-water tissue graft cultured pearls from China contain domains of calcite, emitting orange cathodoluminescence in the central region, which are almost absent in the natural fresh-water pearls from the Mississippi river. (2) The concentration of Mn2+ in natural fresh-water pearls from the Mississippi river is marked by regular green (λ=566 nm) zones of CL from the middle up to the periphery, whereas in case of the tissue graft fresh-water pearls from China the Mn2+ concentration decreases from the middle towards the periphery of the pearl as it is revealed by the gradually diminishing of CL towards the periphery. Whole specimen of the two types of pearls mentioned above can be distinguished from one anotherwithout destroying the samples using a cold cathode cathodoluminescence microscope as follows: The intensity of CL at 566 nm emitted from the surface of natural fresh-water pearls from the Mississippi river is higher than the intensity of CL emitted from the surface of fresh-water tissue graft cultured pearls from China, due to the fact that the surface layers of the former pearls contain more Mn2+ than those of the later.
A further criterion of the Chinese tissue graft cultured pearl is the utmost smoothness of their surfaces. Moreover according to AFM observation the size of the aragonite crystals on the surface of the Chinese fresh-water tissue graft cultured pearls is much smaller than those of natural fresh-water pearls from the Mississippi river.
KeywordsAragonite Tissue Graft Mississippi River Atomic Force Microscope Observation Aragonite Crystal
Unable to display preview. Download preview PDF.
- BANERJEE, A., 1996, Schwarze Perlen aus Tahiti:Natur und Museum, v. 126, p. 209–216.Google Scholar
- BANERJEE, A. and HABERMANN, D., 1998, Comparison of manganese contents of fresh water pearls by a hot cathode cathodoluminescence microscope.Abstract Vol. IMA 17thGeneral Meeting, p. A. 74.Google Scholar
- BANERJEE, A., 1999, Correlation between Mn2+ concentration and cathodoluminescence of pearls:Beihefte zum European Journal of Mineralogy, v. 1, p. 66.Google Scholar
- BROWN, G., 1981, The Biwa pearl:Australian Gemmologist, v. 14, p. 186–193.Google Scholar
- BROWN, G., 1983, Direct X-radiography of pearls:Australian Gemmologist, v. 11, p. 105–121.Google Scholar
- CUIF, J.P., DAUPHIN, Y., STOPPA, C., and BEECK, S., 1996, Shape, structure and colours of polynesian pearls:Australian Gemmologist, v. 19, p. 205–209.Google Scholar
- FARN, A., 1986, Pearls, natural, cultured and imitation. Butterworths, London, 114 p.Google Scholar
- FRAUSTO DA SILVA, J.J.R., and WILLIAMS, R.J.P., 1991, The biological chemistry of the elements: The inorganic chemistry of life. Oxford University Press, Oxford, p. 370–384.Google Scholar
- HABERMANN, D., 1997, Quantitative hochauflösende Kathodolumineszens-Spektroskopie von Calcit und Dolomit, Dissertation, Ruhr-Universität Bochum.Google Scholar
- KOMATSU, H., 1985, Chemistry of pearls:Gemmology (Japan), v. 12, p. 356–359.Google Scholar
- LORENZ, I. and SCHMETZER, K., 1985, Möglichkeit und Grenzen der röntgenographischen Untersuchungen von Perlen:Zeitschrift der Deutschen Gemmologischen Gesellschaft, v. 1, p. 57–68.Google Scholar
- NEUSER, R.D., 1995, A new high-intensity cathodoluminescence microscope and its application to weakly luminiscing minerals:Bochumer geologische und geotechnische Arbeiten, v. 44, p. 116–118.Google Scholar
- RIEDEL, G., 1928, Die Flußperlmuscheln und ihre Perlen. Linz, 294 p.Google Scholar
- SREBRODOLSKY, B.I., Generation and growth of biogenic aragonite:Doklady Academy of Sciences of the USSR, Earth Science section, p. 152–154.Google Scholar
- URMOS, J., SHARMA, S.K., and MACKENZIE, F.T., 1991, Characterization of some biogenic carbonates with Raman spectroscopy:American Mineralogist, v. 76, p. 641–646.Google Scholar
- WADA, K., 1970, The structure and formation of pearls, Profiles of Japanese Science and Scientists. Tokyo, p. 228–244.Google Scholar
- WADA, K. and FUJINUKI, T., 1988, Factors controlling minor elements in pearls:Journal of the Gemmological Society of Japan, v. 13, p. 2–12.Google Scholar
- WALDECK, H. and KIEFER, W., 1970, Untersuchung von Natur-und Zuchtperlen durch Neutronen-aktivierungsanalyse:Zeitschrift der Deutschen Gemmologischen Gesellschaft, v. 19, p. 34–43.Google Scholar
- WASSOWIAK, R., 1962, Geochemische Untersuchungen an rezenten Molluskenschalen mariner HerkunftFreiburger Forschungshefte, v. C 1, 136 p.Google Scholar
- WEBSTER, R., 1994, Gems, their sources, description and identification. London, p. 500–505.Google Scholar
- WILBUR, K.M. and YONGE, C.M., 1964, Physiology of Molluscs. v. 1, New York, 22 p.Google Scholar