Treatment Tracer

April 1998

Gemstones & Pearls:Gemology

Treatment Tracer

Groom Gematrat makes it easier to identify what lurks in your emerald

Determining clarity enhancement in emeralds has just become easier.

Groom Gematrat, the New York City company that introduced a new epoxy resin filler last year, has added a tracer that will make the material easier to identify when it is used to enhance an emerald's clarity.

There's Only One
The tracer is present only in Groom Gematrat treatments and isn't a factor in determining any of the many other emerald treatments, including cedarwood oil (which has been used for decades) and other epoxy resins (of which there are several thousand kinds).

There are so many treatments, in fact, the Gemological Institute of America's sophisticated laboratories list only "evidence of clarity enhancement" rather than determine exactly which one it is.

Cap Beesley of the American Gemological Laboratory in New York City says making such distinctions isn't hard. His reports currently list and identify "Opticon-like" resins and cedarwood treatments.

Arthur Groom of Groom Gematrat agrees with GIA that without conclusive identifiers for every form of treatment, it's unfair to distinguish any. Various oils and epoxy resins have different life spans, different optical effects and different durabilities. But Groom wanted to make his treatment as identifiable as possible so jewelers would have no doubt.

The treatment was already identifiable because of its lower refractive index than any other known resin. But now the addition of the tracer will authenticate the filler as Groom Gematrat. It consists of microscopic uniquely striped particles of a registered material that doesn't obstruct the clarity or durability of the treatment. Lab technicians can quickly identify the treatment with 120X magnification, says Groom. He hopes it soon will be identifiable under 30X to 60X magnification, making it even easier for jewelers to confirm.

"The tracer particles also have a unique fluorescence pattern under short-wave ultraviolet light," he says. No pictures of the characteristic particles or the fluorescence patterns were available at press time.

More Developments
Groom also updated his technology for the cleaning and infilling process at his lab. A new- generation machine speeds the infilling process by 70%. "We have learned a lot about the efficiency of vacuuming, the spread of the resin within the emerald and effects of various resin mixes," he says. "We've learned how different emeralds behave under different conditions."

The Groom Gematrat pro-cess applies controlled low heat in a sterile environment – the heat is no stronger than an emerald would experience during the cutting process. The process prepares an emerald for the vacuuming and subsequent infusion and even distribution of filler.

Groom says emeralds re-spond differently depending on the nature and size of the inclusions. When selling a clarity enhanced emerald, it's important to tell consumers how rare it is to find an untouched gem.

"I love to defend the concept of an unenhanced emerald," he says. "But it is interesting to consider that a fine gem emerald that requires no enhancement is rarer than a pink diamond."

by Robert Weldon, G.G.

Copyright © 1998 by Bond Communications.


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