2022 CGA Gem Conference, October 21-23 – Vancouver, BC
Over the next several weeks, the Roskin Gem News will feature the guest speakers who presented at this year’s conference.
This week, we focus on gemmology.
One of the dozen+ guest speakers for this year’s conference was Shane McClure, Global Director of Colored Stones Services for the Gemological Institute of America Laboratory.
In McClure’s review of “what is still out there,” he reminds us all that “any gemstone can be clarity enhanced if it has surface reaching fractures or cavities.”
He spoke on the commonly expected clarity enhancement of emerald, but also mentioned that the laboratory sees its fair share of clarity enhanced ruby, as well as clarity enhanced copper bearing tourmalines. As you would expect, GIA’s laboratory performs exhaustive examinations to report on any clarity enhancement.
McClure made a special note that any gem, but most commonly emerald, can come to the lab with none or minor enhancement, and then once it leaves the laboratory, can be further enhanced if the gemstone allows. The laboratory clearly states on the report that the findings of the lab are made “at the time of examination.” One should always have the gem verified with the lab if you believe there has been any additional clarity enhancement since the time the laboratory examined the gem.
Emerald and “Paraiba” copper bearing tourmaline enhancements includes oils, resins, & polymers.
Ruby clarity enhancement commonly includes high lead content glass as well as silica glass.
McClure mentioned that the lab is still seeing Titanium surface diffused sapphire, but not only with natural sapphire. You cannot assume that the gem is natural simply because it has been treated. Check any diffusion treated stone to see if it is natural or synthetic as well.
Other gems mentioned being commonly diffusion treated include:
Sapphires – beryllium diffusion
Spinel – cobalt diffusion
(… and coated Tanzanite… not really diffusion, but while you are looking, you may encounter this as well.)
Speakers for the 2022 Vancouver Conference: