Lab Games Part II
Gem Science: Playing Catch-up:
"Ploy Nua On" is the Thai name for a stone known in English as chrysoberyl. The burner just discovered in 1995 how to use a beryllium rich atmosphere to lower the blue content in sapphire and create in some cases an additional yellow color and by 1999 the first Beryllium treated padparadscha were in the market. .The dreaded Beryllium diffusion treatment was born.
What is Beryllium diffusion and how does it differ from plain old heat treatment? The key word is diffusion, a foreign element, beryllium is added to the stone. With traditional low-temperature heating nothing is added. This type of heat treatment has been going on for several thousand years. High temperature heating began in the 1970s and does actually involve hydrogen diffusion but on grading reports it is typically called “heat only” , has been accepted as “traditional” by the market and has dramatically less effect on price than Beryllium diffusion.
The AGTA laboratory put out a warning in January, 2002 http://www.agta.org/consumer/gtclab/orangesapphirealert.htm just before the big
This is a perfect example of the catch-up game that gemologists must play. Technology improves, new treatment methods are discovered by accident or on purpose and the laboratories first must determine that something is being done and then what is being done. In this case with a time lag of seven years.
Boldly going where No Lab-rat has gone before.
Gemological Laboratories are under increasing pressure to add quality grading to their traditional role of determining origin and treatment of gemstones. One laboratory, AGL had been doing this for several years. However, recently under the aegis of the Lab Harmonizing Committee several of the leading labs have decided to aggressively go where no lab has gone before into the world of marketing. Gem Labs have entered the nomenclature business and into a firestorm of controversy .The question of nomenclature is often more about tradition than science. You can study internal inclusions and make a determination about treatments and point out what specific anomalies led to your conclusions but how do you decide what to name a gem? The recent flap over
Traditionally we name a gemstone based on species and variety but what happens in the case of a gem that is of the species corundum but derives its name strictly from a mix of colors? What gem am I thinking of? I’ll give you a hint; padparadscha sapphire.
In my book Secrets Of The Gem Trade, The Connoisseur’s Guide To Precious Gemstones, www.secretsofthegemtrade.com, following the late great GIA gemologist Richard Liddicoat, I define padparadscha as a light to medium tone of pinkish orange to orangey pink. Up until recently, labs have avoided the issue by simply calling the colors; “pinkish orange” and so forth.
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I get emails but no comments!
This blog gets a lot of readers but I am disapointed by the lack of comments. Am I preaching to to choir or are there people who strongly disagree? I realize that a good many of my readers are magazine writers, clients, collectors, editors and gem and jewelry lovers not working professionals. Seems to me that the lab issue is one that dealers, gemologists and students of gemology would want to think about. Imagine a world in which everything from the grandest ruby to the humbalist garnet has a certificate that tells you all about it, everything including how good it is.
Perhaps you don't comment because you are looking for a job in a gem lab and you know that the net is a little like the difference between true love and herpies. The desease and the internet are forever.
The speed and ease of the internet make it so easy to communicate that sometimes you end up disagreeing with yourself. In the "good" old days published opinions were considered final. Today they should not be so considered. I think of my posts to be an intellectual work in progress. I claim the right to change my mind. So, please, comment away, I welcome your input.