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Current turnaround time at the AGTA GTC 5–7 Business Days |
By Richard Hughes
Acetone is sometimes used to clean specimens prior to taking an FTIR spectrum, the idea being that this will remove surface contaminants. But one must take great care that the acetone itself is not contaminated, as the following two spectra show.
FTIR spectrum of the same orange sapphire taken before (red) and after (blue) the gem was dipped in acetone. One can clearly see that the acetone has actually contaminated the specimen, producing large oil peaks where only tiny ones existed before. |
In Tucson I performed a brief experiment that shows the potential perils of acetone cleaning as it relates to the FTIR. First, the FTIR spectrum was run on the specimen without any sample preparation other than wiping with a gem cloth. Then, the gem was dipped into a bottle of acetone that had been previously used to clean many specimens. Following a quick dip, the excess acetone was removed with a paper towel (without touching the gem) and the spectrum re-run. The result was distinctive, with large oil peaks found following the acetone bath.
This simple experiment makes clear that acetone dipping has many perils with the FTIR. As a powerful solvent, it will dissolve oils and other dirt that might be on the specimen, but this then leaves a residue as the acetone evaporates. Even if the gem is carefully wiped clean following this dipping, one can suppose that residue would still remain in pits and fissures that escape the touch of the wiping medium.
The lesson is that acetone "cleaning" may add contamination, rather than remove it. If acetone is to be used at all (and the above suggests it should not), one should use clean acetone for every dipping.
Dr. John Emmett had the following comments on the idea of cleaning a specimen in acetone prior to testing with the FTIR:
Washing a stone in anything without knowing the spectra of it is not advisable. First, use semiconductor-grade solvents and only use them once. Second, know the spectra of the pure solvent so you know where in the spectrum to look for interferences and for solvent in cracks. Third, you can measure the spectra of even volatile solvents by putting a drop between two pieces of polished synthetic sapphire plates. Run the spectra of the plates without solvent first. Using paint store solvents for multiple cleanings is worse than no cleaning.
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Treated Ruby With Multiple Personality Disorder
By Dr. Lore Kiefert
We received a large ruby (>10 ct) for identification. Microscopic examination revealed evidence of high-temperature heat treatment, to an extent where we were not even sure if it was a natural gemstone. When immersed in di-iodomethane, a telltale orange rim was seen, suggesting beryllium diffusion. Before doing LIBS testing for beryllium, we performed EDXRF to determine natural versus synthetic origin. The chemistry not only revealed the gem to be natural (due to the gallium content), but it also revealed the presence of lead. LIBS testing gave us a stronger than normal beryllium peak.
Just how does a gem end up with both beryllium and lead? Good question. Lead is a component of some fluxes. In addition, lead is a major component of the glasses used to fill fractures in ruby. We speculate that the gem may have originally been filled with lead glass and later beryllium treated. The lead-glass treatment is normally done at low temperatures, while beryllium diffusion takes place at much higher temperatures. This was a gem with a true multiple personality disorder.
The ruby in question. Photo: Judy Chia/AGTA GTC. |
This overview shows that the gemstone was originally heavily fractured and subsequently flux healed. Photo: Hpone-Phyo K. Nyunt/AGTA GTC. |
High magnification revealed that the bubbles were surrounded by a darker fluid, which has not been observed in "traditional" flux healing. The size of the bubbles is approximately 5 μm. Photo: Lore Kiefert/AGTA GTC. |
Synthetic overgrowth on the surface of a re-polished ruby indicates that the gemstone was heated at high temperatures. Such a phenomenon has been observed in many of the pinkish orange Be-treated sapphires. Photo: Hpone Phyo K. Nyunt/AGTA GTC. |
LIBS spectrum for the ruby in question, showing the strong beryllium peak at 313 nm. |
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Thai and Japanese Trade Associations Reach Beryllium Agreement
On March 14, 2007, representatives of the Thai Gem and Jewelry Traders Association (TGJTA) and Japan Jewelry Association (JJA) announced an agreement regarding the disclosure of beryllium (Be) treatments in corundum. Other signatories were the Thai Department of Export Promotion (DEP) of the Thai Ministry of Commerce; the Gem and Jewelry Institute of Thailand (GIT); and the Chanthaburi Gem and Jewelry Traders Association (CGA).
The memorandum states that exporters of loose corundum must disclose the treatment on invoices using the following terminology:
The JJA asked that the same disclosure rules also be applied to jewelry set with corundum.
In Thailand, compliance with these rules is to be enforced under the rules of the TGTJA, while the JJA confirmed that its members must follow the same disclosure standard in their domestic transactions. Cases of non-compliance will be dealt with under the rules of the Japanese association.
Both parties resolved to establish a set of similar disclosure standards for beryllium identification with support from gem laboratories in both countries. In addition, both parties will ask their local gem labs to conduct joint research in order to strengthen the disclosure procedure.
For corundum exported to Japan without proper disclosure and subsequently found to contain beryllium, the Thai exporter shall accept the return of the gemstone and make a full refund to the buyer. However, TGJTA requested that the disclosure procedure should also be applied by all other countries that export corundum to Japan. The JJA said it would give this issue its highest priority.
The TGJTA proposed to the JJA to make information about beryllium treatment available to the downstream market, i.e. to the retail and consumer levels. The JJA welcomed this proposal.
Finally, the TGJTA proposed to create a "Cluster Blue Sapphire Group" that would export only non- Be-treated corundum. Once such a group is formed, the list of member companies will be made available to the JJA and will be distributed among its members.
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Upcoming Lectures
AGTA GTC staff will be busy in the coming months with the following lectures:
Pasadena, CA, Saturday, March 31, 2007 
Known to the Chinese as the "Stone of Heaven," jade is one of mankind's most beguiling gemstones. While the term "jade" includes both nephrite and jadeite, only jadeite occurs in the coveted "imperial" type, and for this the world has but one source, Upper Burma. It is these mines which are the subject of this program.![]()
Washington, DC, Monday, April 9, 2007, GIA Alumni, DC Chapter
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 be 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.
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Carlsbad, CA, Saturday, April 21, 2007, Sinkankas Jade Symposium
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Denver, CO, April 25–28, 2007, AGS Conclave 
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Staffing Updates
There have been two recent staff changes at the lab. We sadly say goodbye to Riccardo Befi, who has left to join the colored diamond department at the GIA. The entire lab wishes the best to Riccardo in his new position. ![]()
We also send a warm welcome to the newest gemologist at the AGTA GTC. Marina Epelboym is a graduate in chemistry (BSc, with honors) from Technological University in the Ukraine. Prior to her arrival in the US 13 years ago, she worked as a chemist, conducting analyses of multi-elemental samples by spectral methods. In the US, Marina joined EGL USA, performing fancy-colored diamond analyses and participating in gem identification, including country-of-origin determinations. Marina also served as head officer in the diamond grading department of EGL USA. Besides her BSc in chemistry, Marina received an FGA diploma in 2003, and a certificate of attendance in modern micro-analytical techniques for gemologists from Kingston University in London, in 2006.
With Marina, we will have yet another experienced gemologist with a solid scientific background, making the laboratory stronger than ever.
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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.