How to read a lab report - question about a sapphire

[Gailey]

At the weekend, a Canuk Gal and I were in a high end mall jewellers.

Once the owner could see that we had some gem knowledged he was anxious to show us a couple of sapphires that he claimed were complely natural. One was a hot pink. I don''t remember the size but it was substantial. It was C$19,000 and came with an EGL certificate that said, "No evidence of heat".

So my question is, how ambiguous is EGL''s opinion? Does, "No evidence of heat", also mean no BE diffusion or other treatments? I asked him why he had sent it to EGL and not GIA or AGL or even AGTA (the cert was dated 2007). Didn''t get a straight answer to that. So my naturally sceptical nature was already starting to wonder what exactly was I looking at and how much could the cert be relied upon.

Now before you all get excited, no we weren''t on a buying trip, just "kicking tyres".

 

[T L]

EGL is typically used by jewelers because they're known in the trade for giving hugely inflated appraisal values. I'm unaware how good their in-house gemologists are, but typically if a sapphire has not been heat treated, that means it is not be-treated. You require heat for diffusion. GIA, AGL, AGTA do not provide estimated replacement values on their laboratory certs. EGL does. I am also not aware if they have the expensive machines that are used to detect diffusion either.

My guess as to why jewelers use these lab reports like IGI, EGL, UGL, with appraisals, is that they probably turn stones around quicker, give large appraisal values, and are probably less expensive to the trade. However, labs like GIA, AGTA (which I think is now closed for grading), and AGL, are more highly respected, and they all have the latest state of the art equipment. They know most consumers aren't aware of the value of the lab grading the stone, so they go with these other lesser known labs.

 

[Gailey]

Sorry, I wasn''t clear. The price was set by the jeweller, not appraised as such by EGL.

 

[T L]

Sorry Gailey,
An affiliate of EGL, Universal Gemological Services (I called them UGL above) are the ones that give overly inflated appraisals. I am unaware of how precise their evaluation is, since the information on a certificate is some gemologist's opinion, and not all gemologists are created equal. We depend on very good laboratory equipment as well as gemologists that are very familiar with colored gems (most only know how to grade diamonds). I don't know enough about EGL, but I would put most of my trust in AGL above all other labs for colored gems, even GIA, GRS, and some others. AGL is really the premier lab for colored gems, and for me, if I were buying any very expensive colored gem, I would require an AGL.

 

[Gailey]

TL, yup, I pretty much feel the same way you do, and said as much.

He also had a pretty nice looking spess (6.68 cts, C$5500) and paraiba (1.88 cts, C$9950) and they had certs from a Vancouver lab I''d never heard of. The spess was particularly nice looking, fanta orange and very, very clean. So clean in fact I was suspicious.

I think he could tell I liked the spess because he gave me his card with the details of the spess and paraiba on the back.

If there was ever a day I was going to spend that kind of money, any stone would have to have an AGL cert and come from either Peter, Roger or Lisa''s shop.

 

[chrono]

If it the cert says no evidence of heat, it means it isn’t heated. This includes no BE diffusion because that requires high temperature heating. I, too, prefer AGL, GIA, AIGS, GIT, GRS, and of course, the now closed AGTA for my coloured gemstone memos for the obvious reasons but will never limit myself to the usual favourite vendors because one never knows who might have what you are looking for at that time. After all, the favourite vendors are now the usual favourites because a PSer “discovered” them, took a chance, found the transaction very satisfactory and never looked back.

 

[lelser]

EGL and CGL have the advantage of being in Canada, and both are good labs for most of the things I need done. Shipping a stone out to GIA or AGL gets expensive not just for the shipping and insurance, but for the little brokerage fees that the carriers slap on.

I''ve got a basic lab myself, and certify my own stones but a few where I need more equipment go into CGL. Only once have I had a stone that was too difficult for the local lab and needed to be sent off to GIA. It was something I had on consignment and just wouldn''t resell with ambiguous results.

 

[Sagebrush]

All,

All labs have their strengths and weaknesses. GIA, AGL and Gueblin (Lucern) is excellent as is SSEF in Germany and GRS in Bangkok (particularly for Ruby & sapphire). Many people who buy premium gems will ask for a cert from both an American and European lab.

The wording is legalese. AGL uses the terms "based on existing gemological information" in essence the lab call is the lab''s opinion and is, in fact, based on existing data---change the data as in a new treatment and the situation changes. The consumer community wants to set that opinion in stone but the labs want to "chisel" out of it. Fact is the bad guys come up with the treatments and the good guys try to catch on and their is frequently a time lag.

Best,