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Published March 1994 | metadata_only
Journal Article

The Anahí Ametrine Mine, Bollvia


The Anahí mine, Bolivia, has produced large amounts of amethyst, citrine, and amethyst-citrine for the gem market. Field and experimental investigations conclusively show that the amethyst-citrine color combination in quartz crystals from Anahi is natural and does not result from laboratory treatment. The unusual color patterns probably result from the uncommon geologic conditions under which these quartz crystals formed, although the crystal chemical properties controlling the sector color zoning still elude explanation. From 1989 to the present, more than 100 tons of ametrine crystals, yielding 40-80 kg of cutting rough per ton, have been produced.

Additional Information

© 1994 Gemological Institute of America. The authors thank M&M personnel, particularly Don Ramiro Rivero, for providing access to the Anahf mine, field support, samples, and information on mine production. The White Rose Foundation kindly supported laboratory studies. The senior author also thanks Francisco Mansur, Domingos Reis, Roberto Colen, Anne Marie Kitos, Brent Lords, and John Donovan for their contributions.

Additional details

August 22, 2023
August 22, 2023