The National Association of Jewelry Appraisers is scheduled to host a special workshop for gemologists and jewelry appraisers on how to identify synthetic diamonds and diamonds that have been subjected to treatments.

The Cross Polarized Filter Workshop, to be held January 29 at the Tucson Convention Center, will include both a lecture and practical training in the use of the Cross Polarized Filter.

In December, the Gemological Institute of America hastened to assure the public and the diamond trade that it was still possible to identify synthetic diamonds, even stones produced through the Chemical Vapor Deposition (CVD) method. The GIA announcement came after the Gemesis diamond company announced that it would begin producing colorless synthetic diamonds and selling them online.

Workshop participants can register through the NAJA website (NAJAappraisers.com/conferences.html) or fax or e-mail a request to the NAJA at naja.appraisers@netzero.net. Registration deadline is January 15.