About the AGTA Gemological Testing Center
The AGTA Gemological Testing Center is the natural colored gemstone industry’s premier independent laboratory providing the industry and the public with a complete range of services, including gemstone identification, origin determination and pearl identification. The laboratory, located in New York City, is equipped with the latest, technologically advanced, investigative equipment.

    The AGTA Gemological Testing Center's primary objectives are:

  • To identify the nature of all materials that are likely to be used as gemstones and report upon them in a clear and scientifically precise manner for the public and the jewelry trade.
  • To produce reports on these materials in a manner that assists both the trade and the public in assessing a potential purchase.
  • To research all aspects of gem materials in order for their characteristics to be fully understood.

Separation of Natural and Enhanced/Treated Gems
A special enhancement section appears on AGTA Gemological Testing Center reports to assure that all gemstone treatments or enhancements are properly identified. This reporting method is consistent with AGTA's enhancement information policies. For both rubies and emeralds, the AGTA GTC quantifies the amount of either residue from the heat process or clarity enhancing substances, if present, as a normal identification service. It will also, upon request, identify the type of clarity enhancing substance present in emeralds.

Origin Determination of Ruby, Sapphire and Emerald
As a special "by request only" service, the AGTA Gemological Testing Center uses the latest analytical techniques and its extensive gemstone database to support a professional opinion concerning the geographic origin of either ruby, sapphire or emerald.

Separation of Natural and Synthetic Gems
Sophisticated synthetic stones require intricate methods to identify them. The AGTA Gemological Testing Center employs the latest technology to ensure the reporting of accurate results.
    The AGTA Gemological Testing Center is among the few gemstone laboratories that offer separation of natural and synthetic amethysts. In many cases, the testing is more expensive than the value of the amethysts themselves. This service is most often used by AGTA members to audit the supply chain through random testing of shipments from mines and cutting factories.

Separation of Natural and Cultured Pearls, along with Artificial Coloration
The AGTA Gemological Testing Center will examine pearls to determine their natural or cultured origin. In the case of beaded, nucleated, cultured pearls, the AGTA Gemological Testing Center may also, upon request, state the thickness of the nacre covering.
    The AGTA GTC will also determine the natural or artificial nature of the color of natural and cultured pearls.

Separation of Natural and Artificially Colored Diamonds
Got diamonds? No problem. The AGTA Gemological Testing Center can identify the nature of the apparent color, or lack of color, in a diamond. UV/visible low temperature spectroscopy is used to analyze colored diamonds and to determine if the color is natural or due to artificial irradiation. The AGTA GTC's Raman micro-spectroscopy unit is employed to examine colorless diamonds that are suspected of being decolored by High Pressure High Temperature (HPHT) treatment.

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.
Problems? Praise? Contact the Webmaster.


The AGTA GTC publishes free bulletins with the latest gem news. Sign up here.


Site Search

search tips     sitemap