AGL Issues Warning About Irradiated Colombian Emeralds

Although rumors about treated emeralds have been rife for a number of months, the lab says this was the first time it had received stones that have been identified as being irradiated – a procedure that was first shown to modify the color of natural and synthetic emeralds nears 20 years ago.

AGL said in a release that although the color of the emeralds was slightly unusual for a typical Colombian emerald, color alone cannot distinguish treated gems. Instead, detection is most effectively carried out using a spectrometer (an instrument used to measure properties of light over a specific portion of the electromagnetic spectrum) since the treatment may produce different types of defect centers that absorb in the ultraviolet region of the spectrum.

“Interestingly, we also noted that these emeralds had been clarity enhanced by introducing a polymer-type resin into fissures to reduce their visibility,” said Christopher P. Smith, president of AGL. “So these particular gemstones had the standard emerald enhancement of clarity, as well as an additional enhancement of irradiation.”

According to AGL, the amount of irradiated emerald in the marketplace is currently unknown. The lab is urging suppliers to be aware of the situation and encourages other laboratories to be on the lookout for this treatment.