AGTA GTC Laboratory Update
March 4, 2008
In this message…
Upcoming Seminar on Ruby & Sapphire Treatments
Following the success of their recent seminars in California and New York, the AGTA GTC has scheduled a new date. 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 sessions where participants 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
- 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. Photo: Hpone-Phyo K. Nyunt/AGTA GTC. |
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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. Photo: Hpone-Phyo K. Nyunt/AGTA GTC. |
Donations Sought for Reference Collection
The AGTA GTC is now offering educational seminars. In order to have the most comprehensive reference collection ready for these seminars we are seeking donations. We are still missing certain gemstones such as ruby from Tajikistan, emeralds from North Carolina and Zambia, and many others as well as natural and treated South Sea and Tahiti cultured pearls. If you have specimens you believe might be useful for education, please contact us.At the same time, we would like to publicly thank those who have already provided donations, including Ray Zajicek, Bob Kane, Betty Sue King, Peter Bazar, Omi Nagpal, Glenn Lehrer, Tracy Jukes and Barbara Lawrence. All of these people have been extremely supportive over the past years.
In the recent past, we received donations from Warren Boyd of Tsar Emerald, John Bradshaw, Azotic, Leslie and Swarovski, Mexifire, Thomason Stone Supply, Mawingu Gems, Perlas del Mar de Cortez, and many others. Thanks to all of you and any that are not mentioned here.
Just a portion of the reference collection to which seminar participants have access. Photo: Hpone-Phyo K. Nyunt/ AGTA GTC. |
Tucson Wrap-up
AGTA GemFair™ Tucson is now complete and was a big success, with the GTC's Mobile Laboratory taking in more gemstones than any previous year.
In addition to testing gemstones and giving lectures, the AGTA GTC staff was treated to a personal viewing of a number of fine gems, courtesy of the Smithsonian Institution's Russell Feather. These included the Logan Sapphire, which features a 422.99 ct Sri Lankan sapphire.
For several years, Russell Feather and Dr. Jeffrey Post of the Smithsonian Institution have organized private viewings for the AGTA GTC staff of the museum specimens on display at AGTA GemFair™ Tucson. This year we were not disappointed, as Russell Feather brought in several outstanding examples of why the Smithsonian Institution's National Gem Collection is one of the biggest draws in the world. Oo's and ah's were heard as one amazing piece after another was brought out for viewing and examination.
We extend our most sincere thanks to Russell Feather and Dr. Jeffrey Post for making these viewings possible and can hardly wait until next year!
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| The AGTA GTC's Marina Epelboym holds the Logan Sapphire. The Smithsonian Institution's Russell Feather dropped by the AGTA GTC Mobile Laboratory at GemFair Tucson with this and a number of other goodies for examination by our staff. At 422.99 ct, the Logan Sapphire is one of the world's largest fine sapphires on public display. Photo: Richard Hughes/AGTA GTC. |
Treated Green Amber
In the summer of 2007, the AGTA GTC received some beads that were sold as green amber. We did extensive research on these beads and could not confirm natural amber at this stage. Not only did the properties not match these of natural amber, they also did not match those of any known amber imitation.
Normally, natural amber gives off aromatic fumes when heated. The fumes from the tested samples were not quite as aromatic as we would expect for natural amber. In addition, the samples were not easily attacked by chloroform or ether, and on top of that, there were some peaks missing in the FTIR spectrum. However, the FTIR spectrum was completely different than all known plastics.
Our client generously gave us the contact address from his supplier, Mr. Mueller of Facett Art in Idar-Oberstein. After a first contact, we received additional amber pieces in all different stages and could see some of the amber peaks get weaker at the same rate the amber got greener.
Going a bit more into the details, Facett Art let us know that they have taken some old patents and refined them (Figure 1).
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| Figure 1. Some of the old patents that can be found about the heat treatment of amber. Photo: Lore Kiefert/AGTA GTC. |
This involves a heating process utilizing an autoclave, but not all amber is suitable for treatment. This company uses amber from the Ukraine, near the area of Kaliningrad. At one of the satellite shows in Tucson, a Chinese company is also selling green amber, supposedly derived from South American amber.
At the end of 2007, I had the opportunity to visit the company Facett Art in Idar-Oberstein. Mr. Mueller showed me around, including his faceting facility (Figure 2) and described his treatment process.
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| Figure 2. Mr. Mueller is demonstrating the faceting of his green amber in his office in Idar-Oberstein. Photo: Lore Kiefert/AGTA GTC. |
In a two-step process, the amber is first heated moderately to see if any further treatment will result in the desired green color. Afterwards, the amber is re-heated in an autoclave using a higher temperature and some pressure. During the process, a dark brown viscous residue remains. After the second step in the heating process, the amber gets its clear green color (Figure 3), but only 20–30% of the samples can be changed like that.
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| Figure 3. A large drop-shaped green amber. Photo: Lore Kiefert/AGTA GTC. |
In the big piece (Figure 4), there is still some milkiness in the center. One possible explanation for the modified amber properties is the following: The "amber acid" is the volatile component of the amber that gives it the smoke and the smell and probably the peaks that were missing in the infrared spectrum. This component is "pressed" out of the amber using temperature and pressure. What remains behind are the more stable parts of the amber.
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| Figure 4. This large piece of yellowish green amber still shows some cloudiness in the center, demonstrating that the heating process did not completely affect the whole piece. Photo: Lore Kiefert/AGTA GTC. |
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| Figure 5. Treated green amber. Photo: Lore Kiefert/AGTA GTC. |
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| Figure 6. Treated green amber. Photo: Lore Kiefert/AGTA GTC. |
World of Gems Conference
The AGTA GTC is pleased to announce that they are co-sponsoring the upcoming World of Gems Conference along with Richard Drucker's Gemworld International.
When & Where
- September 13–14, 2008, Chicago, IL, at the Hyatt Regency O'Hare. Mark your calendars now.
Cost
- Only $395.
- Sign up by May 1, 2008 and save $50; AGTA Members and GemGuide subscribers save an additional $50.
- Conference fees not only include two days of seminars, but also breakfast and lunch both days and a cocktail reception on Saturday evening.
- Rooms are just $135/night, with Hyatt quality. Compare this to conferences where rooms are typically $200/night and more.
Why You Should Attend
- Cutting edge information, including treatments and pricing
- Top industry speakers
- Prime networking opportunities
- Incredible value for the money
- Free user meetings for industry products
- New products at special conference prices
- Free perks for attendees
