AGTA GTC's Laboratory Update for July 11, 2007
In this message…
- GTC Reports: New Look
- Large Purple Sapphire
- Michael Scott Collection is Back at Bowers
- AGTA GTC Advanced Treatment Seminar
GTC Reports: New Look
The American Gem Trade Association recently launched a new brand campaign unifying its image as The Authority in Color™. Building on this, the AGTA GTC will soon be issuing reports reflecting this new look. Here is a sneak peek:
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For anyone interested in replacing existing reports with the new reports, we are offering a special rate for a limited time. Through September 1, 2007, reprints of reports with the new look can be purchased for $30 (AGTA Members) and $40 (non members). The regular replacement rate will be $35 (AGTA Members) and $45 (nonmembers). Save today!
Large Purple Sapphire
We recently received from a European client a 164-ct purple sapphire for testing that was exceptional not only for its size and rich, purple color, but also for its extreme clarity. Other than two tiny feathers on the crown and a faint, straight blue zone in the center, the stone was completely free of inclusions. Gemological properties were typical for corundum:
Refractive index: |
1.762–1.770 |
UV fluorescence: |
LW: Strong red SW: Medium red |
Visible spectrum: |
Cr and Fe spectrum |
Trace element chemistry: |
Ti: 0.072% V: 0.013 Cr: 0.073 Fe: 0.283 Ga: 0.026 |
This 164-ct purple sapphire recently tested by the AGTA GTC is one of the largest exceptional fancy sapphires we have had the pleasure to test. Photo: Hpone-Phyo K. Nyunt/AGTA GTC. |
Gems! Colors of Light and Stone: The Michael Scott Collection back at the Bowers Museum
For those who missed it last time around, the Michael Scott Collection is back at Bowers Museum in Santa Ana, California. Scott has assembled the most important private gem collection in the United States, one that has few rivals in the world.
GEMS! Colors of Light and Stone is among the most important exhibitions of colored gemstones, diamonds and gems as art ever shown in a U.S. museum. It not only includes spectacular examples of cut stones of the major gem varieties, but also crystals, jewelry and magnificent gem carvings, including those by German artists Bernd Munsteiner and Gerd Dreher and the work of Seattle-based silversmith, John Marshall.
In addition to the gem exhibition, the museum is putting on a number of lectures on gems. For more details, contact the Bowers Museum at 2002 N. Main St, Santa Ana, CA 92706; Tel: 714-567-360. Don't miss the chance to see this stunning exhibit.
The AGTA GTC Advanced Treatment Seminar
Today's gem market is literally in flux, as scientific advances produce an ever-changing landscape of gemstone treatments. To help dealers, jewelers and collectors keep pace with these developments, the AGTA GTC has developed an intense one-day educational seminar covering advanced treatments for ruby, emerald and sapphire. This seminar features:
- Limited class size
- Hands-on sessions with actual gem samples
- Expert instruction from AGTA GTC gemologists
Each section begins with a brief review of the major treatment technologies and the AGTA GTC's Gemstone Report nomenclature for that type of gem. This is followed by an intensive laboratory session, where participants personally examine samples. Each of the following topics are discussed during the one-day program:
1. Advanced Ruby Treatments
- No thermal enhancement (NTE)
- Thermal enhancement (TE)
- Minor through significant flux healing (TE1–TE5)
- Minor through significant glass cavity filling (C1–C3)
- Minor through significant glass fracture filling (F1–F3)
- Lab methods for identifying these treatments
- Chromium diffusion (orange and red)
- Multiple treatments
2. Advanced Emerald Treatments
- No filler (NF)
- Minor through significant fissure filling (F1–F3)
- Stones with both oil and resin fillers are featured
- Lab methods for identifying the presence of a filler and distinguishing between oil and resin fillers
3. Advanced Sapphire Treatments
- No thermal enhancement (NTE)
- Thermal enhancement (TE)
- Titanium diffusion (blue)
- Beryllium diffusion (orange, yellow, red, blue)
- Synthetic overgrowth
- Multiple treatments
- Lab methods for identifying these treatments
If you are interested in participating in seminars, please contact Loretta Castoro at 212-752-1717 or via email at loretta@agta-gtc.org.
| Testifyin': Comments from Recent Seminar Participants
"Education is the best weapon against fraud. This class is a must for gem dealers who want to know what they are buying." Barbara Lawrence "This comprehensive seminar on the detection of sapphire, ruby and emerald treatments is essential for everyone in the gem trade." James Alger |
