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Published September 1986 | public
Journal Article

Relationships between radiation damage and trace water in zircon, quartz, and topaz

Abstract

The presence of trace amounts of water or hyroxide ion can dramatically affect the response of a mineral to radiation from both internal and external sources. In zircon, where radioactive decay of U causes structural damage (metamictization), water can enter the structure after a threshold of damage is reached and stabilize the metamict state by annealing local charge imbalance. Quartz crystals with both amethyst and citrine zones have molecular water in the citrine zones and dominantly hydroxide ion in the amethyst zones. This may be due to the reduction of the amethyst Fe(IV) color center by atomic H formed by radiolysis of the water. In topaz, special hydroxide sites correlate with the formation of a brown color center. The crystallographically identified hydroxyl on the (OH,D site does not appear to be correlated with radiation damage. The mobility of H and the ease with which H-O species may be formed in silicates appear to explain much of the role of hydrous species in radiation-damage processes in minerals. These species occur in several charge states and may anneal local charge imbalance. The occurrence of trace amounts of water in even nominally anhydrous minerals makes this interaction common.

Additional Information

© 1986 Mineralogical Society of America. Manuscript received May 24, 1985; manuscript accepted May 16, 1986. We thank James Woodhead and Leon Silver (California Institute of Technology) for helpful discussions and collaboration in the study of zircon metamictization. R. H. Currier (Arcadia, California) provided and carefully described the history of the Indian amethyst-citrine samples. Other samples were provided by Kurt Nassau (Bell Labs) and by Vince Manson of the Gemological Institute of America (Santa Monica, California). J. B. Parise provided helpful discussions on topaz and kindly shared his samples with us. This work was funded, in part, by National Science Foundation Grants EAR-7723147, EAR-7919987, and EAR-8313098.

Additional details

Created:
August 22, 2023
Modified:
October 23, 2023