Hi everyone. I have a bit of a problem. I bought an AGS stone and took it to an independent appraiser who is a master gemologist. Everything was fine (color, clarity, weight) until the appraiser measured the diameter. The appraiser measured it 0.02 mm smaller on the low end and 0.03 mm smaller on the upper end than what the cert claims. The appraiser did this with two different tools (digital and analog), which he says are correctly calibrated. We both (I really wanted to prove him wrong and not have to worry about all this) tried measuring and re-calibrating many times over. It also happens that the diamond came with an OGI report which showed the exact same measurements as the two tools used by the appraiser. The appraiser said that in his 35 years of experience, he hadn''t seen such a large discrepancy and advised me to talk to the seller.
I talked to the jeweler over the phone and explained the situation. I stopped by later in the day and he told me that he had called another master gemologist in the area and that he thought the discrepancy can be explained by variance in the tools. The jeweler also said that he called AGS and got the same response. Then he went on to insinuate that the first appraiser was not good at his work (which I found to be quite unprofessional of him, but that''s besides the point).
I am an engineer and I have a difficult time buying the "variance" argument. Yes it''s true that all instruments are slightly different and that environmental conditions affect readings, but it''s not terribly difficult to design a tool that varies by less than 0.01 mm in most environments. We reset the digital caliper several times and kept getting the exact same results. Also, three different measurement techniques came up with the same exact answer... that''s hard to discount.
The reason I''m posting here is that my appraiser feels very strongly about this and has even offered my money back to find someone else to appraise the stone. I left a message for a rep at AGS, but while I''m waiting to hear back, can any appraisers that visit this forum give me their experience with this? Do you see these kinds of variances often? Even so, should the stone be sent back to AGS (this affects the cut proportion after all: 62.1% instead of the stated 61.9%) or should I just find another appraiser to finish the job?
I talked to the jeweler over the phone and explained the situation. I stopped by later in the day and he told me that he had called another master gemologist in the area and that he thought the discrepancy can be explained by variance in the tools. The jeweler also said that he called AGS and got the same response. Then he went on to insinuate that the first appraiser was not good at his work (which I found to be quite unprofessional of him, but that''s besides the point).
I am an engineer and I have a difficult time buying the "variance" argument. Yes it''s true that all instruments are slightly different and that environmental conditions affect readings, but it''s not terribly difficult to design a tool that varies by less than 0.01 mm in most environments. We reset the digital caliper several times and kept getting the exact same results. Also, three different measurement techniques came up with the same exact answer... that''s hard to discount.
The reason I''m posting here is that my appraiser feels very strongly about this and has even offered my money back to find someone else to appraise the stone. I left a message for a rep at AGS, but while I''m waiting to hear back, can any appraisers that visit this forum give me their experience with this? Do you see these kinds of variances often? Even so, should the stone be sent back to AGS (this affects the cut proportion after all: 62.1% instead of the stated 61.9%) or should I just find another appraiser to finish the job?
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