I have no link to post for you since this was in Ron's newsletter this week.
Gem Labs; Points to Ponder
Gem Labs and Their Machines
Last year I brought a 3.11 carat emerald to a gem lab and told the director there that my emerald had oil in one fissure; I had oiled it myself with equipment in my office. I was expecting a ‘minor’ degree of enhancement outcome on the certificate from that laboratory. However, the stone came back to me with the certificate stating “no evidence of clarity enhancement.” I spoke to the lab manager about it and he said that the FTIR and Raman didn’t detect any oil.
”But I oiled it,” I said.
“Nothing was detected.” He replied.
Not wanting to start an argument, I left with the stone even though I told him at the beginning that I personally oiled that one small fissure. In this manner I gained a perspective on how gem laboratories trust their machines and nothing else.
Of course, it mostly happens the other way around; an emerald dealer brings in a stone that has no oil and the certificate comes back ‘minor’ as you can read below.
Muzo Emerald
A similar thing happened to me when working at the Muzo emerald mine cutting center (CTT) in Bogotá’s free trade zone. When a rough stone is expected to be cut into a “no oil” emerald, company policy has it moved to another part of the building where no clarity enhancement takes place; the cutting machines and equipment are all reserved for non-enhanced emeralds and not even the tweezers or stone cloths have ever touched oil.
I brought the resulting stone to the upcoming Tucson show and after taking it to one of the laboratory locations at the show, I was informed that the stone was ‘minor’ degree of enhancement. I tried to argue the point, especially because microscopic examination revealed nothing, but the lab director insisted he was right, even stating that the enhancement was with resin. I was amazed at how confident he was with his machines.
Gem Lab directors all have a certain “glow” about them – you know what I mean. This particular director however, lost some of his glow in my eyes.
I think the conclusion here is: you can’t argue with a machine (and lab directors only trust machines).
“Approximate Degree of Enhancement: Minor”
As I have said before, I don’t want to criticize gem labs as ineffectual; I just want to make the point that the determination of emerald clarity enhancement is difficult; so difficult that all labs should precede their determinations with the word “approximate” on the certificate. (Stop laughing! I’m an idealist! Maybe it will happen some day!).
Some Definitions Need Reviewing
The word enhance is defined as: “to raise or increase to a higher degree”. In the case of clarity enhancement of gemstones, the definition is “to increase the apparent visible clarity and beauty.”
And yet, to my dismay, I sometimes see an emerald with diamond powder or white cutting powder in a fissure, being called out on a certificate as “evidence of clarity enhancement”. What? The material in the fissures (as well as whitish old dried out oil or wax) is in reality Un-enhancing that stone! That is, the emerald is uglier because of something in a fissure.
Don’t we all agree that clarity enhancement of emeralds should be a visually detectable improvement? And it should be determined by estimating how the emerald would look without the oil or resin, right? And yet gemologists still find non-transparent things in fissures and call it clarity enhancement!
Theoretically, it should be the case that, when the “clarity enhancement” is removed the emerald should look worse; it should be uglier. But that is often not the case. Many of my emeralds that have certificates stating ‘minor’ would not change appearance when the oil or enhancement is removed. Why? Because of the location and amount of the oil that was discovered in the stone is sometimes ridiculously small. Those of us who perform clarity enhancement in our offices see this: the stone looks the same with or without being oiled. Of course go ahead and state on the certificate that junk was found in a fissure but don’t call it enhancement!
One Swiss gem lab director confided to me that “finger oil” could throw off the reading of their machines. A rare admission when you consider that gem labs constantly promote their infallability. The ‘glow’ of this particular person grew to me, rather than diminished.
It is hoped that this discussion will continue as the World Emerald Symposium draws nearer.
Ron Ringsrud
This air-filled fissure in a Colombian emerald does not come to the surface. It cannot be enhanced or oiled or changed. I don't know what the hell those small dust-like particles are in the fissure. But I do know that gemologists will be tempted to call it polishing powder or "foreign material." Gemology tries to be scientific but there are many subjective calls; calls based on experience that is impossible to teach to new gemologists. Why is the fissure so green? It is not green; the fissure is simply reflecting light from other parts of the stone.
