Following months of investigation, the American Gem Trade Association (AGTA) has issued a warning concerning the extent to which synthetic materials are being misrepresented as natural colored gemstones. This practice appears particularly prevalent in larger and better-quality amethyst and citrine.

As a partial solution to this problem, the AGTA introduced low-cost “batch testing” services in its Gemological Testing Center. The technique, developed by laboratory director Ken Scarratt, allows for the low-cost and rapid testing of large quantities in sample lots, using Fourier Transform Infrared (FTIR) spectroscopy, in addition to more conventional testing procedures.

The AGTA GTC has been batch-testing samples of amethyst for some time and has released monthly data from January 1999 to July 2000. A total of 2,791 stones was tested and 472 stones represented as natural were conclusively determined to be synthetic.

American Gem Trade Association, Box 420643, Dallas, TX 75342; (800) 972-1162 or (214) 742-4367, fax (214) 742-7334, Web site: www.agta.org.