Welcome to AGTA GTC's Laboratory Update for May 24, 2005

In this message

  1. Seeing in the Dark, Part 2: UV Fluorescence as a Gem Dealer’s Tool 
  2. Meet our Staff: Dr. Lore Kiefert
  3. The AGTA GTC in Las Vegas

Seeing in the Dark, Part 2:
UV fluorescence as a gem dealer’s tool

In a previous installment (May 9, 2005), we looked at the use of UV fluorescence as a simple but powerful tool. Below are a few more examples illustrating how the technique can help in certain identifications.
     We’d like to thank everyone who took the time to write to us regarding this article. Some of you also wanted to know how the photos were taken. Below you will find illustrations of this, too.

Figure 1.  Fluorescent fillers in emerald
Emeralds are typically treated by filling their fissures with oils/resins. Some of these fluoresce. In the photo above, an emerald is exposed to long-wave UV light. The filler in the fissures is clearly identified by its bluish fluorescence. Note that the body color of the gemstone appears much different under UV light. Photo: Richard W. Hughes/AGTA GTC

Figure 2.  Additional examples of fillers in emerald
Two different filled emeralds under LW UV light. Photos: Henry Hänni/SSEF

Figure 3.  Pink Sapphire
Similar to blue sapphires and rubies, when some pink sapphires are heat treated, they will display a zoned chalky fluorescence in short-wave UV light, as shown above. Photo: Richard W. Hughes/AGTA GTC

Figure 4.  Photographing fluorescence
The author took the photos in these articles using the following crude set-up. A stoneholder was taped to a gooseneck arm to hold the gemstone in place. Photos were shot with a Nikon D70 digital camera with a Nikon 60mm macro lens. Also used were two Nikon screw-on close-up lenses, to further increase magnification. Exposures were made in manual mode with a wireless shutter release, with all ambient (room) lights turned off. Photo: Richard Hughes/AGTA GTC

Figure 5.  Another view
Another view of the author’s photo setup. Photo: Richard Hughes/AGTA GTC


Meet our Staff:
Dr. Lore Kiefert – Laboratory Director
Lore Kiefert (born in Heidelberg, Germany) began studying Mineralogy in 1981. In 1987, she obtained her Master's degree with a thesis on the distinguishing characteristics of sapphires (natural vs. synthetic as well as different origins). After this, she changed direction and went to Australia to gain her Ph.D. on the composition of desert dust.
     In April 1994 she joined the SSEF Swiss Gemmological Institute, beginning her distinguished gemological career. Lore joined the SSEF, when the organization was located in Zürich, as Assistant Director. The SSEF moved to Basel in the same year.
    Lore was awarded her Ph.D. in 1996 and her FGA (Diploma in Gemmology) early in 1998, and was appointed Director of the SSEF Colored Stones Department in 2000.
    Lore is a prolific writer, authoring a large number of scientific and gemological papers. Indeed, the latest issue of the Journal of Gemmology (January/April 2005) alone contains three different papers she co-authored. In addition, Lore has contributed to the Handbook of Raman Spectroscopy and the Handbook of Raman Spectroscopy in Art and Archaeology. She has lectured at numerous scientific and gemological conferences in Australia, South Africa, the United States, England, Belgium, Czech Republic, Austria, Holland, Germany, and various places in Switzerland.
    Lore brings great expertise both in colored gemstone identification and origin determination to the GTC.


The AGTA GTC in Las Vegas
Once again, the AGTA GTC will be participating in The JCK Show - Las Vegas 2005, offering a range of gemological services, such as:

  • Identification reports for all kinds of gems, including the identification of clarity enhancement fillers
  • Country-of-Origin reports for ruby, sapphire and emerald.

    The AGTA Pavilion has special dates and times! The AGTA Pavilion opens and closes one day before the main JCK show. The AGTA GTC Mobile Laboratory, located in the AGTA GemFair Cultured Pearl & Jewelry Pavilion, is open Thursday, June 2nd–Monday, June 6th. Hours are 10:00am to 6:00pm on June 2nd and 9:00am to 6:00pm from June 3rd–6th. The AGTA GTC Mobile Laboratory is planning to deliver the reports to clients within 1–2 days and the services are going to be available during the show time.
     But even better than submitting gemstones during the show, is to submit them to the AGTA GTC prior to the show. By doing so, you'll have the gemstones in your showcase, ready for sale with reports. Gemstones submitted by Wednesday, May 25th, will be returned to you at the show. Hurry up and have your gemstones tested today!


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. The laboratory, which is located in New York City, is equipped with the latest, technologically advanced, investigative equipment.
     The AGTA GTC is committed to providing excellent service, superior value and outstanding quality. A complete list of services and detailed pricing information is available on our website, www.agta-gtc.org. Please contact us with any questions.


American Gem Trade Assocation Gemological Testing Center
18 East 48th St., Suite 502
New York, NY 10017, USA
Tel: 212-752-1717; Fax: 212-750-0930
E-Mail: info@agta-gtc.org; Web: www.agta-gtc.org
© 1999–2005 American Gem Trade Assocation Gemological Testing Center. All rights reserved. Users may download this information for their own private, non-commercial use. Any other reproduction of this document (text or graphics) without the express written consent of the AGTA GTC is strictly prohibited.
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