AGTA GTC's Laboratory Update for January 10, 2008
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AGTA GTC Seminars on Ruby & Sapphire Treatments Filling Fast
Following the success of their recent seminars in California and New York, the AGTA GTC is scheduling new dates. Designed to help dealers, jewelers and collectors keep pace with the latest ruby and sapphire treatment developments, this intense one-day seminar features:
- Limited class size (maximum six participants)
- Hands-on sessions with actual gemstone samples
- Expert instruction from AGTA GTC gemologists
Sessions begin with a brief review of the major treatment technologies and the AGTA GTC's Gemstone Report nomenclature. These are followed by laboratory session where participant personally examine samples, concentrating on separation of untreated gemstones (NTE) from the following treated gemstones:
- Heat (TE)
- Flux healing (TE1 to TE5)
- Glass cavity filling (C1 to C3)
- Glass fracture filling (F1 to F3)
- Oils, dyes and irradiation
When and where
- Friday, January 25, 2008, at the Carlsbad, CA AGTA GTC
Morning: 9:30 a.m. to 12:30 p.m.; Lunch: 1 hour; Afternoon: 1:30 to 4:30 p.m. - Tuesday, March 18, 2008, at the New York AGTA GTC
Morning: 9:30 a.m. to 12:30 p.m.; Lunch: 1 hour; Afternoon: 1:30 to 4:30 p.m. - Cost: $800 per person
To register, or if you are interested in participating in future seminars, please contact Dr. Lore Kiefert at 212-752-1717 or email at lkiefert@agta-gtc.org. Special arrangements can be made for groups of six participants.
What others have said... "I recently participated in one of the greatest classes of my career on December 3, 2007. I learned a tremendous amount of useful information on corundum. Having attended seminars offered by other associations, I now know AGTA has the highest standards. I appreciate the honor of attending this class and look forward to more. Deborah A. Villepigue "Education is the best weapon against fraud. This class is a must for any gem dealer who wants to know what he or she is buying." Barbara Lawrence |
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Left to right: Cindy Wolfsohn, Thomas Edwards, Teri Newman Brossmer, the AGTA GTC's Richard Hughes, Courtney Balzan and Charles Carmona view images of treated corundums as a prelude to lab work during the November 16, 2007 seminar in Carlsbad, CA. |
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Richard Hughes (center right) discusses the finer points of the spectroscope with Courtney Balzan (left) and Charles Carmona (far right) during the November 16, 2007 seminar. |
Glass-filled Rubies More Common in US Market
Over the past few months, glass-filled rubies have become more prevalent in the US market, with increasing amounts of glass seen in certain specimens. In one specimen seen in Thailand, glass appears to form a significant portion of the specimen, raising the question of whether or not the piece could even be considered to be ruby.
An additional factor in these is the lead (Pb) content of the glass. This could possibly pose a health risk for jewelers working with the gemstones.
The AGTA GTC currently describes glass-filled rubies in the following fashion:
| Enhancement: | Indications of heating, TE |
| Significant clarity modification, F3, C21 | |
| Species: | NATURAL CORUNDUM |
| Variety: | RUBY |
| Comments: | 1A lead glass has been identified as the filler. Lead glass filler may be unstable to elevated temperatures and to chemical agents. Special care shall be taken when repairing jewelry items set with lead glass filled corundum. This report has been prepared in accordance with the standardized language and criteria set out by the Laboratory Manual Harmonization Committee (LMHC); see reverse. |
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| A gas bubble floats within a glass-filled area of a glass-filled ruby. Note the significant undercutting of the softer glass areas. Photo: R.W. Hughes |
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| This ruby is riddled with glass-filled fractures. Photo: Lore Kiefert |
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| Resizing the ring in which this gemstone was once mounted damaged the glass filling in the fissures of this treated ruby. Photo: Lore Kiefert |
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| Glass-filled ruby with large amounts of glass present. The glass has a higher luster than the corundum, due to the Pb content. Photo: Lore Kiefert |
Further reading
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McClure, S.F. et al. (2006) Identification and Durability of Lead Glass-Filled Rubies, Gems & Gemology, Spring, Vol. 42, No. 1, pp. 22–34.
