AGTA GTC Laboratory Update
June 17, 2008
In this message…
- Unusual Melo Pearl Imitation
- New Sri Lankan Sapphire and Tanzanite JewelFolios
- Upcoming Seminar
- World of Gems Conference
Unusual Melo Imitation
Recently, a large "Melo pearl" weighing 66.30 ct was submitted to the lab (Fig. 1). The pearl showed the flame structure as seen in natural melo pearls. However, there was also visible banding, as seen in shell material, and some orange color concentration along some of these bands (Fig. 2). No polish marks were seen that would suggest it was a worked material. The pearl was almost round, with a diameter varying between 20.19 and 20.80 mm.
Melo pearls come from the Melo melo marine snail, which is found in the waters of the South China Sea, as far south as Singapore and west as the Andaman Sea. Like conch pearls, the melo gem is not actually a nacreous pearl because it contains no nacre. Like the better known pink conch pearls, melos are non-nacreous and show a distinct flame structure. Just like in coral, the orange color is derived from carotene.
The pearl submitted to the laboratory matched the color of a melo pearl, but the banding was suspicious, being unlike anything we had previously encountered in a natural melo pearl. A Raman spectrum was taken and compared to the Raman spectrum of a paler melo melo shell. While the pale yellow shell showed clear carotene peaks, the much more saturated pearl was lacking these peaks (Fig. 3).
With the lack of natural color, plus the banding not seen in natural melo pearls, we concluded that this must have been cut out of a shell. The only one that could give such a big diameter and at the same time exposing flame structure is the giant clam, Tridacna gigas, which can reach up to four feet in diameter. Giant clams are white in color, hence the specimen we had was dyed to imitate a melo pearl.
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| Fig. 1: This "melo pearl", weighing 66.30 ct with a diameter of over 20 mm, was submitted to the laboratory for testing. |
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| Fig. 2: A closeup of the surface shows flame structure, interrupted by repeated banding. Orange color concentration is found in the banding. |
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| Fig. 3: Raman spectrum of a melo melo shell (bottom). Besides the aragonite peaks at approx. 1088, 707, and 210 cm-1, some additional carotene peaks at 1530 and 1138 cm-1 can be seen. These are lacking in the spectrum of the melo imitation (top). |
New JewelFolios on Tanzanite and Sri Lankan Sapphire
AGTA GTC is proud to announce the latest edition to its JewelFolio™ line of premium reports, the Tanzanite and Sri Lankan Sapphire JewelFolios.
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| Title page of the latest AGTA GTC JewelFolio™, the Sri Lankan Sapphire. |
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| Early Portuguese map of Sri Lanka featured in the newest AGTA GTC JewelFolio™, the Sri Lankan Sapphire. |
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| Fingerprint in a Sri Lankan sapphire. Like all JewelFolios, the Sri Lankan Sapphire JewelFolio™ features a blend of history and science, reuniting gemology with its romantic and legendary roots. |
Like all JewelFolios, the Sri Lankan Sapphire JewelFolio™ is a custom-built one-of-a-kind document for a one-of-a-kind jewel. Each JewelFolio™ consists of a hardcover cloth or leather-bound volume that will be a companion to an individual jewel. Volumes are based around a type of gemstone and/or origin.
In addition to Tanzanite and Sri Lankan Sapphire, the following JewelFolios are also available:
- Kashmir sapphire
- Colombian emerald
- Burmese sapphire
- Burmese ruby
Contents
Every JewelFolio™ consists of approximately 32–42 full-color pages and features the following:
- History, legends and lore
- Modern and antique maps and photos
- Color photos illustrating both rough and cut gemstones and inclusions
- Detailed testing information on the specific specimen, including advanced tests
- Macro and microphotographs which will separate the specific specimen from all others
- Reproduction of the standard AGTA GTC Origin Report
- References for further reading and care instructions
In addition to the above, JewelFolios are individually numbered, making each a collector’s item.
Cost
JewelFolios are lavish documents for lavish objects, and represent an entirely new paradigm in the realm of gemological laboratory reports. See our fee schedule for full pricing information.
Summing Up
People are drawn to precious gemstones because of passions, not just properties. The purchase of a gemstone is an emotional contract that connects the new owner with people and places across the planet. Bonding modern science with romance and history, the AGTA GTC JewelFolio™ rekindles desire, reinforcing the connection to the places and cultures from which these treasures come.
Welcome to the AGTA GTC JewelFolio™ – a truly new direction in gemology.
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| Like all JewelFolios, the Tanzanite JewelFolio™ features a blend of cultural and artistic information. |
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| Modern tanzanite jewelry inspired by traditional African themes. |
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| Tanzanite grading defined. |
Upcoming Seminars on Ruby & Sapphire Treatments
The AGTA GTC has scheduled new dates for their seminar on Ruby & Sapphire Treatments. Designed to help dealers, jewelers and collectors keep pace with the latest ruby and sapphire 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
- Monday, June 30: Fallbrook, CA
- Friday, Aug. 8: New York, NY
- Monday, Sept. 15: Chicago, IL
- Monday, Oct. 27: Fallbrook, CA
- Monday, Dec. 8: New York, NY
Each session is 9:30 a.m. to 12:30 p.m. and 1:30 to 4:30 p.m., with a one-hour break for lunch. The cost is $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..."It was great to work with someone as experienced as you. I learned a tremendous amount and it was worth every penny. I would even consider taking it again, or a slightly altered version of it in the future as well, just to get some more hand's on experience with you. One of the best parts about [yesterday's course] was being able to work with actual treated/natural stones while you are there to help. I already posted on Orchid (the jewelers' news group) a note about how great the course was and am recommending it to everyone. (PS, I've already spent a bunch of time – that I should be spending on customers' jobs – looking at some of my sapphires under the microscope to confirm a few of the things I learned.)" Daniel R. Spirer, G.G. |
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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. |
World of Gems Conference
The AGTA GTC is pleased to announce that they are co-organizing 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.
- 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
