AGTA GTC Laboratory Update
May 1, 2007
In this message
- Auction Action
- Burmese Jadeite
- Treated Sapphire with Multiple Personality Disorder
- Secrets in Sapphire: Mystery Inclusions in Rutile Silk
- AGTA GTC Mobile Laboratory in Las Vegas
- Upcoming Lectures
Current turnaround time at the AGTA GTC 5–7 Business Days |
By Dr. Lore Kiefert & Richard Hughes
Christie's New York's Magnificent Jewels sale on April 25th, 2007 shattered two important records. Lot 262, the Baroda Pearls, a two-strand natural pearl necklace with ear pendants, brooch and ring en suite fell for a stunning $7,096,000. This is an auction world record for a natural pearl jewel. The previous record was set by Christie's Geneva in November 2004 at $US3.1 million, for a two-strand natural pearl necklace.
But this was not all. Lot 261, a 22.66 ct cushion-shaped Kashmir sapphire pendant, more than doubled the previous record for a sapphire, selling for a whopping $3,064,000 ($135,216/ct). This gemstone featured an AGTA GTC Origin Report and the pre-sale estimate was $250,000–350,000. The previous record of $3,031,000 ($48,871/ct) for the 62.02 ct. Rockefeller Sapphire was set in 2001. That sapphire hailed from Burma.
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In addition to these record setters, a pearl and diamond necklace was submitted to the AGTA GTC prior to auction. Originally thought to be cultured pearls and with a pre-sale estimate of $12,000–18,000, they proved to be natural pearls. Sale price? $135,000. Value of an AGTA GTC Pearl Report? Priceless.
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By Richard Hughes & Dr. Lore Kiefert
A piece of jadeite jade brought in for testing recently was intriguing in a couple respects. First were the inclusions. While one does not normally think of distinctive inclusions in jadeite, this gemstone possessed a clear cluster of crystals, including many which broke the surface and displayed a much higher luster than the surrounding jadeite. Micro-Raman analysis identified these as zircon, which had been previously identified in jadeite by John Koivula and Tom Moses in 1998 (Gems & Gemology, Vol. 34, No. 1, p. 45).
A cluster of zircon inclusions in jadeite jade. Photo: Richard W. Hughes/AGTA GTC. |
The same group of zircons seen in reflected light breaking the surface and displaying high luster. Note also the small (black) pits and microfractures, which suggest bleaching. Photo: Richard W. Hughes/AGTA GTC. |
In contrast, the surface of an untreated jadeite shows only major cracks. Absent is the network of tiny microfractures created by bleaching. Photo: Richard W. Hughes/AGTA GTC. |
FTIR of polymer-treated jadeite performed with both the DRIFTS and beam condenser methods. Click on the image to bring up a large image of these spectra. |
In addition to the zircon inclusions, the specimen displayed a network of fine cracks that suggested it had previously been bleached. Bleaching is the first stage in the common B-jade process where jadeite is bleached to remove foreign matter from its pores and then the tiny micro-fissures are impregnated with either a wax or polymer, greatly improving both color and clarity.
Such treatment is typically unmasked by reference to FTIR spectra. When we first checked the FTIR spectrum via the DRIFTS method (see FTIR Intrigue), large polymer peaks were found. A recheck with the beam condenser method revealed the same polymer peaks, but at reduced levels.
Treated Sapphire With Multiple Personality Disorder
By Dr. Lore Kiefert & Hpone-Phyo K. Nyunt
Following on our previous report of a ruby with multiple personality disorder, we tested a sapphire showing the same schizophrenia. The sapphire weighed close to 7 ct and showed orange fluorescence with a blue rim in LW UV, and chalky blue fluorescence in SW UV. The pavilion surface and parts of the crown was covered with a multitude of minute fingerprints induced by heat, as well as surface pits. When a white diffuser plate was used, color was found concentrated on the surface, exactly following the facet pattern, indicating lattice ('surface') diffusion with titanium. EDXRF showed 0.185 wt% Ti (usual Ti concentrations are approx. 0.01%).
In addition to the unusual color pattern, a group of small feathers were seen on the surface, suggested prolonged heating at high temperatures. On a lark, we performed a LIBS test and found a distinct Be peak with LIBS at 313 nm. The result? The gemstone was not only titanium diffused, but also beryllium diffused, yet another corundum with multiple personality disorder.
Diffused light reveals concentrations of color at the surface and facet junctions, suggesting lattice diffusion. Photo: Hpone-Phyo K. Nyunt/AGTA GTC. |
Shallow fingerprints in the same gemstone, caused by prolonged high-temperature heating. Photo: Hpone-Phyo K. Nyunt/AGTA GTC. |
Secrets in Sapphire: Mystery Inclusions in Rutile Silk
By Richard W. Hughes
From the beginning of my gemological studies in 1979, I have been intrigued by inclusions and none have provided greater fascination than rutile silk. I never tire of gazing at these gossamer-like strands in untreated ruby and sapphire.
Initially, I was attracted to the brilliant colors; later, I learned to appreciate their structural details, noting that what I first regarded as single crystals were actually microscopic twins with tiny re-entrant angles at the broad ends.
Over the past few years, I've noticed a further hidden detail. Virtually all exsolved rutile needles large enough to be clearly resolved with my microscope (up to 70x magnification) show tiny daughter crystals at the broad end, implanted directly in the re-entrants.
What are these hidden mysteries? Mostly likely, they are impurity phases forced out of solution with the rutile, probably something like hematite (trigonal Fe2O3) or ilmenite (trigonal FeTiO3). We are currently in search of a specimen where these daughter crystals are both large enough and close enough to the surface for analysis.
High magnification reveals that well-formed rutile silk generally has tiny daughter crystals growing at the broad ends. Untreated blue sapphire. Click on the photo to bring up a larger version. Photo: Richard W. Hughes/AGTA GTC. |
Again, tiny daughter crystals are clearly visible at the broad ends of rutile arrows in this untreated blue sapphire. Click on the photo to bring up a larger version. Photo: Richard W. Hughes/AGTA GTC. |
For more on rutile silk, see Following the Silk Road: Rutile Silk in Corundum.
The AGTA GTC Mobile Laboratory in Las Vegas
Once again, the AGTA GTC will be participating in The JCK Show – Las Vegas 2007, offering a range of gemological services, such as:
- Identification reports for all kinds of gemstones, including the identification of clarity enhancement fillers.
- Country-of-origin reports for ruby, sapphire and emerald.
The AGTA Pavilion has special dates and times, opening and closing one day before the main JCK show. The AGTA GTC Mobile Laboratory, located in the AGTA GemFair Cultured Pearl & Jewelry Pavilion, is open as follows:
- Dates: Thursday, May 31st to Monday, June 4th.
- Hours: 10:00 AM to 6:00 PM on May 31st and 9:00 AM to 6:00 PM from June 1st–4th.
The AGTA GTC Mobile Laboratory will deliver reports to clients within 1–2 days and services will be available during normal show hours.
Show fee schedules
- Mobile Laboratory Fee Schedule for AGTA Members
- Mobile Laboratory Fee Schedule for AGTA GTC Associate Program Members
- Mobile Laboratory Fee Schedule for Nonmembers
Upcoming Lectures
AGTA GTC staff will be busy in the coming months with the following lectures:
Las Vegas , NV, May 30–June 4, 2007, AGTA GemFair Las Vegas
- Solid Steps to Successful Colored Gemstone Sales
Douglas K. Hucker, American Gem Trade Association
Wednesday, May 30, 2007, 3:30–4:30 PM
AGTA's Executive Director explores the critical components of a dynamic and successful colored gemstone jewelry presentation. What motivates your customer to buy color? What are their major concerns when doing so? Learn the basic components that must be included in every presentation to dramatically improve your success rate. Identify your most powerful sales tools, including a thorough discussion of the AGTA GTC Colored Gemstone report, and the critical part they play in the sales presentation.
- Update from the AGTA GTC Laboratory
Dr. Lore Kiefert, AGTA GTC Laboratory
Thursday, May 31, 2007, 9:00 –10:00 AM
The AGTA laboratory comes across many materials and treatments before they hit the market. Knowing about these new developments on the gemstone market, as well as having an idea what to look for, will help you make the right decisions in your buying and selling of gemstones. AGTA's scientists focus on colored gemstones.
- Increase Sales by Empowering Your Team with Knowledge
Loretta Castoro, AGTA GTC Education Consultant
Thursday, May 31, 2007, 3:30–4:30 PM
AGTA GTC is launching training opportunities for your use in staff development. In this preview session, you have sample segments of gemological seminars, which include how to empower your staff to comfortably engage in communicating about colored stones with your clients. These seminars build confidence by providing the most current gemstone knowledge available in the industry.
Pasadena , CA, Friday, June 8, 2007, Pasadena City College
- People & Places: New Directions in Gemology
Richard W. Hughes, AGTA Gemological Testing Center
Friday, June 8, 2007, 7:30 PM
Pasadena City College
Geology Dept, E Building, Room 220, 1570 E. Colorado Blvd., Pasadena, CA
Gemology is tired. Weary. Stumbling. Guilty. We are privileged to work with some of the most stunning and romantic objects on the planet – singular marvels of incredible beauty. And yet all we can do is analyze. Like sadists, we torture beauty until the extraordinary is reduced to the ordinary – chemicals, numbers and digits – abstractions with no relation to the reasons why people are drawn to precious stones. We break the butterfly upon the wheel.
Which instrument comprehends feeling? What tool measures emotion? No device can see with our eyes nor read our minds. Yet we surrender our senses to the machine. Guilty as charged. We break the butterfly upon the wheel.
Gemology cannot become simply science. People are drawn to precious stones because of passions, not just properties. The purchase of a precious stone is an emotional contract that connects the new owner with people and places across the planet. If we wish to fathom desire, we must begin understanding this visceral link. And if answers are not easily measured, if they involve emotion and art, not just science, they are no less real and no less important to gemology.
Richard Hughes will delve into these issues via a dramatic multimedia presentation that covers ground all the way from Manhattan, through Russia's emerald mines, to Madagascar and Tajikistan's remote ruby, sapphire and spinel deposits.
It will provide inspiration, a new direction into the neglected, nether regions of gemology. Don't miss it.
Idar-Oberstein, Germany, June 22–24, 2007
- Emerald and alexandrite from the Malysheva Mine, Ural Mountains, Russia
Dr. Lore Kiefert, AGTA Gemological Testing Center
June 22–24, 2007
Stadttheater/City Theater, Idar-Oberstein, Germany
First European Gemmological Symposium: "Present and Future of Gemmology"
Honoring the 75th Anniversary of the German Gemmological Association, this international symposium will take place June 22–24, in Idar-Oberstein, Germany, and will offer presentations by gemological researchers and business leaders from the gem and jewelry industry.
Santa Ana , CA, Saturday, June 23, 2007, Bowers Museum
- People & Places: New Directions in Gemology
Richard W. Hughes, AGTA Gemological Testing Center
Saturday, June 23, 2007, 1:30 PM
The Bowers Museum
2002 N. Main St, Santa Ana, CA 92706, Tel: 714-567-3600
See description above.
The AGTA Gemological Testing Center provides the industry and the public with a complete range of lab services including gemstone identification, origin determination and pearl identification. Located in New York City, the laboratory is equipped with the latest, technologically advanced, investigative equipment. The AGTA GTC is committed to providing excellent service and superior value. A complete list of services and pricing information is at www.agta-gtc.org. Please contact us with any questions.
