An update on color in gems. Part I: Introduction and colors caused by dispersed metal ions
- Creators
- Fritsch, Emmanuel
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Rossman, George R.
Abstract
Studies concerning the origin of color in gem materials have grown in sophistication in recent years, so that much new information is now available about natural color and its possible modification by various treatment processes. This three-part series of articles reviews our current understanding of gemstone coloration. The first part summarizes the factors that govern the perception of color, from the source of light to the human eye, and then examines in detail the role of one color-causing agent, dispersed metal ions, in the coloration of many gem materials, including ruby and emerald. The second part will explore charge-transfer phenomena and color centers as the cause of color in gems such as blue sapphire and Maxixe beryl. The series will conclude with colors that can be explained using band theory and physical optics, such as the play-of-color in opal and the blue sheen of moonstone feldspars.
Additional Information
© 1987 Gemological Institute of America. E.F wishes to thank Professor Georges Calas, of the University of Paris VII, for his support in writing the original French version of this article. Special appreciation is due to Pat Gray for typing and correcting the "French accent" of the original manuscript. Thanks to Laurel Bartlett, John Hummel, and James Shigley for their constructive comments.Additional details
- Eprint ID
- 38180
- DOI
- 10.5741/GEMS.23.3.126
- Resolver ID
- CaltechAUTHORS:20130430-103432405
- Created
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2013-05-02Created from EPrint's datestamp field
- Updated
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2021-11-09Created from EPrint's last_modified field
- Caltech groups
- Division of Geological and Planetary Sciences