TUCSON '98

We always hope that the Tucson shows will unfold like a great novel, with one resounding gemological theme tying together all the disparate subplots. If there was one great theme this year, gemstone treatment certainly earned that title, although it was the subject for education rather than resolution in Tucson. The International Colored Gemstone Association (ICA) and the American Gem Trade Association (AGTA) sponsored a pre-AGTA-show 'summit' meeting on treatments with representatives from various gemological laboratories. AGTA also put together an informative display on the main show floor concerning some better-known treatments in emeralds (clarity enhancement) and rubies (glass filling). Conversation throughout the shows often centered on the need for treatment disclosure and the efforts being made by AGTA, ICA, and other organizations to promote such disclosure.
 
Again, though, Tucson produced many new and/or different gem materials, or ways of using gem materials. We thank Giulia Goracci and Dr. Ilene Reinitz of the GIA Gem Trade Laboratory in New York, and Carlsbad GIA Gem Trade Laboratory regulars Maha DeMaggio, Cheryl Wentzell, and Philip Owens, in addition to our usual contributors, for their help in providing the following report. More information from the Tucson shows will be presented in upcoming Gem News sections.

DIAMONDS

• Gem crystals from Russia and China.

COLORED STONES AND ORGANIC MATERIALS

• Andalusite (chiastolite) sphere. 
• Coral with a blue sheen from Alaska. 
• Bicolored corundum. 
• Emerald from Tocantins, Brazil.
• Spessartine garnet from Madagascar.
• Sphene from Madagascar.
• Spinel from Vietnam. 
• Parti-colored faceted liddicoatite tourmaline.
• Another tourmaline source in Namibia.

SYNTHETICS AND SIMULANTS

• Synthetic amethyst grown over round seeds. 
• 'Glass stones': Imitation agates. 
• Synthetic moissanite from Russia.

INSTRUMENTATION AND TECHNIQUES

• Buff-top faceted stones cut from quartz spheres.

A PRELIMINARY REPORT FROM THE FIRST WORLD EMERALD CONGRESS

MORE FROM THE 26TH INTERNATIONAL GEMMOLOGICAL CONFERENCE

COLORED STONES AND ORGANIC MATERIALS

• An unusual organic 'gem': Bezoar. 
• Gem-quality transparent feldspar from North America. 
• Libyan Desert glass. 
• Maw-sit-sit from Myanmar. 
• An opal nomenclature. 
• Identifying natural opal in the field. 
• Kashmir rubies. 
• Gemstones of Switzerland.

SYNTHETICS AND SIMULANTS

• First commercial synthetic ametrine from Russia.

INSTRUMENTATION

• Cathodoluminescence and photoexcitation applications in geology.

ANNOUNCEMENTS

• New geologic maps of Sri Lanka. 
• Nature of Diamonds exhibit extended. 
• International Mineralogical Association meeting.

IN MEMORIAM
Charles E. Ashbaugh III, 1944-1997. 
Eugene Edward Foord, 1946-1998.

Editors:
Mary L. Johnson and John I. Koivula
 
Contributing Editors:
Dino DeGhionno - GIA GTL, Carlsbad, California
Shane F. McClure - GIA GTL, Carlsbad, California
Emmanuel Fritsch, IMN, University of Nantes, France
Henry A. Hänni, SSEF, Basel, Switzerland
Karl Schmetzer, Peterhausen, Germany

Appears on pages 50-63