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An Update on Color in Gems. Part 3: Colors Caused by Band Gaps and Physical Phenomena

Fritsch, Emmanuel and Rossman, George R. (1988) An Update on Color in Gems. Part 3: Colors Caused by Band Gaps and Physical Phenomena. Gems and Gemology, 24 (2). pp. 81-102. ISSN 0016-626X.

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The previous two articles in this series described the origins of color in gems that derive from isolated structures of atomic dimensions—an atom (chromium in emerald), a small molecule (the carbonate group in Maxixe beryl), or particular groupings of atoms (Fe^(2+)-O-Fe^(3+) units in cordierite). The final part of this series is concerned with colors explained by band theory, such as canary yellow diamonds, or by physical optics, such as play-of-color in opal. In the case of band theory, the color-causing entity is the very structure of the entire crystal; in the case of physical phenomena, it is of microscopic dimension, but considerably larger than the clusters of a few atoms previously discussed.

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Rossman, George R.0000-0002-4571-6884
Additional Information:© 1988 Gemological Institute of America. E. F. wishes to thank Professor Georges Calas, Mr. Pierre Bariand, and Ms. Anne Voileau for their help and encouragement in writing the original French version of this article. Special appreciation goes to Ms. Pat Gray for typing the original English manuscript and improving the translation, and to Ms. Ruth Patchick for word processing the many revisions, especially the tables. The authors are also grateful to Ms. Laurel Bartlett, Dr. James Shigley, Mr. John Koivula, and Dr. John Hummel for their constructive comments.
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Deposited By: Jason Perez
Deposited On:01 Aug 2013 17:13
Last Modified:26 Nov 2019 11:15

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