Gemstone Treatment Codes

The AGTA has proposed the use of gemstone treatment codes to promote disclosure and a common language for these procedures. Learn what these codes mean.

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By Joel E. Arem, Ph.D., FGA, International Gem Society

The jewelry trade is certainly aware of the possibilities of fraud associated with non-disclosure of gemstone treatments. Various groups (including the Federal Trade Commission) have worked to find solutions acceptable to all parties in the industry. One group, the American Gem Trade Association (AGTA), has proposed a list of "codes" to use as product labels, indicating possible treatments.

natural — This "pink fireball" tourmaline has been classified N, "Natural," according to the AGTA gemstone treatment codes. Photo by Jessa and Mark Anderson. Licensed under CC By 2.0.

AGTA Gemstone Treatment Codes

ASBL - Assembled product
B - Bleaching
C - Coating
CMP - Composite materials
D - Dyeing
F - Filling
H - Heating
I - Impregnation
IMIT - Imitation
L - Lasering
N - Natural
O - Oil/Resin Infusion
R - Irradiation
SYN - Synthetic
U - Diffusion
W - Waxing/Oiling

For more information, consult the AGTA Gemstone Information Manual. Note that consumers should still receive information on enhancements in "plain language," not simply codes. However, hopefully, these codes will promote a "uniform and consistent communication language."

This is an excellent start. One can only hope that awareness, disclosure, and integrity will converge to maintain the health and viability of one of the world's oldest commercial markets.

Joel E. Arem, Ph.D., FGA

Dr. Joel E. Arem has more than 60 years of experience in the world of gems and minerals. After obtaining his Ph.D. in Mineralogy from Harvard University, he has published numerous books that are still among the most widely used references and guidebooks on crystals, gems and minerals in the world.

Co-founder and President of numerous organizations, Dr. Arem has enjoyed a lifelong career in mineralogy and gemology. He has been a Smithsonian scientist and Curator, a consultant to many well-known companies and institutions, and a prolific author and speaker. Although his main activities have been as a gem cutter and dealer, his focus has always been education. joelarem.com

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