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GIA report vs Sarin report

Discussion in 'RockyTalky' started by shearo, Mar 28, 2002.

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  1. shearo
    Rough_Rock

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    by shearo » Mar 28, 2002
    I have recently purchased a diamond from usacerteddiamonds.com and when it arrives I am getting it appraised as suggesed here and on thier website. However when printing out all of the information about the stone I found that the Sarin (I belive its that) report doesn't exactly match the GIA report. My question is, is the GIA report rounded, for example the Sarin report says est 1.03ct whereas the GIA says 1.02, the Sarin depth says 61% whereas the GIA says only 60.8%, for the table Sarin says 54.7% whereas the GIA says 55% etc. Sound I be concerned? Martin Sheffield helped me personally and sounds very trustworthy, however I'm a little concerned with so much at stake.

    GIA -> http://search.virtcert.com/writable/scans/464088-c.jpg
    Report -> http://search.virtcert.com/writable/scans/464088-s.gif
     
    


    


  2. Garry H (Cut Nut)
    Super_Ideal_Rock
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    by Garry H (Cut Nut) » Mar 28, 2002
    Sarin does not 'weigh' the diamond.
    These are normal rounding and instrument variations.
    Nothing to worry about :)
     
  3. bizgk
    Rough_Rock

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    by bizgk » Feb 4, 2005
    Hi,

    I have a similar question, and you seem to know a lot. =) My sarin report (and personal measurement using a measurement device) both indicate a length and a width of about .09mm and .04mm less than the GIA report (it is a princess cut). Is this something that should raise a flag? Might the diamond have been shaved or something?
     
  4. pqcollectibles
    Ideal_Rock

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    by pqcollectibles » Feb 4, 2005
    The Cert labs run a Sarin and that becomes the official Sarin of record for the diamond. No telling how many times a diamond has a Sarin run on it and how many variations there might be. There can be variations from instrument to instrument, technician to technician, etc. Technicians working in one lab all use the same instrument (or instruments calibrated the same) and train to use the same technique. Move the diamond across the steet/town/county, using a different instrument, possibly different technique, and you can get a different result. If you had a HUGE difference you would need to investigate. Nominal differences can be expected. [​IMG]
     
    


    


  5. AgentRHE
    Rough_Rock

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    by AgentRHE » Feb 4, 2005
    The biggest difference on mine between the Sarin and the GIA was the table %, which was 54% on the GIA and 54.9% on the Sarin. Is that a big enough difference that I should be concerned that they ran the Sarin report on the right stone?
     
  6. strmrdr
    Super_Ideal_Rock

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    by strmrdr » Feb 4, 2005
    Im seeing more and more of this lately.
    I have a hunch of why its happening.
    There are a lot of patches and updates flying around and no two people/labs have the same ones applied to the sarin software.
     
  7. AgentRHE
    Rough_Rock

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    by AgentRHE » Feb 5, 2005
    Anybody else hace an opinion on why the GIA on the stone was 54% table, but the Sarin came up with 54.9% This seems like a pretty big difference.
     
  8. pqcollectibles
    Ideal_Rock

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    by pqcollectibles » Feb 5, 2005
    You have to keep in mind that diamonds are measured in millimeters. On a one carat RB, 0.9% difference on the table measurement translates into hundreths of a millimeter. [​IMG]
     
  9. AgentRHE
    Rough_Rock

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    by AgentRHE » Feb 5, 2005
    Ooooh. Good point. And this is a .56 carat we''re talking about, so it''s definitly not a problem. [​IMG]

    Thanks!
     
  10. RockDoc
    Ideal_Rock

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    by RockDoc » Feb 6, 2005
    You''re on the right track with your reply, Storm.

    Sarin has recently upgraded their camera and software.

    They also have different model of Sarin. The lowest cost model, which many jewelers have is the Brilliant Eye.

    As far as I am concerned it is little better than a toy.

    Sarin does have stated variances .... in both percentage reported as well as angle variation.

    Another cause for varying reports can be the gemologist doing the work. The cost of the advanced Sarin''s is about $ 20k or more. GIA has a lot of graders, and I am sure they haven''t invested the money to have one of these machines on each graders cubicle. So probably there is a line to use the Sarin''s and others they do have... and a lot of pressure to produce a lot of reports from each grader.

    My Sarin a lot of times disagrees with the results from the Brilliant Eye, as well as the OGI. But I do have the new camera and software from Sarin. While it isn''t perfect, I do explain to clients that there are variances that are small and normal to expect.
    When there is a "large" discrepancy with another Sarin or lab report, I do my best to find out why such exists.

    Consumers should ask which model Sarin the report is generated from and make sure they are getting all that the machine is capable of doing.

    I do not have an OGI machine. I have talked to others that are sorry they bought one. It just isn''t as accurate as the Sarin.
    For a while OGI had a ray trace light return diagram that was the same for every stone.

    This is an ongoing work in progress, and current up to date software and machines will most likely be improved a lot in the future.

    Rockdoc


    Rockdoc
     
    


    


  11. RockDoc
    Ideal_Rock

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    by RockDoc » Feb 6, 2005
    The Sarin''s weight is an estimate of length width and depth based on a formula using a different factor for each shape.

    Carat is a representation of weight. and I have found the GIA and AGS to report correct weights in almost 100% of the stones sent here.

    Weighing is the only conclusion that I would consider pertinent.

    Rockdoc
     
  12. Richard Sherwood
    Ideal_Rock

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    by Richard Sherwood » Feb 6, 2005
    While this may have been true in the past, it may no longer be a valid claim.

    OGI claims their latest machine, the Novascope, to have greater camera resolution and accuracy than the Sarin. After using it the past couple months, I would have to say I consider it at least as accurate as the top model Sarin.
     
  13. niceice
    Brilliant_Rock

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    by niceice » Feb 6, 2005
    We were running an OGI Mega Scope and found it to be fairly accurate as long as it was calibrated regularly. We "upgraded" that for the Nova Scope and dumped it within a few weeks because we couldn''t get it to run consistently to anything including itself. We brought in a Sarin Dia Mension and love it. Regarding the variance between the GIA reports and the Sarin results, GIA is running a series of Sarin Dia Mensions in the lab each set with the specific lenses for the various size ranges of stones... When we posed this question to Fred Fish at Sarin he indicated that there were times when he had seen technicians at the GIA place the wrong size diamond in a machine with the wrong lens for that size stone because they were in a hurry to meet their quotas for grading... We see enough of a variance between the GIA and the Sarin results on some stones to think that there may be some validity in this statement, some stones run dead on to the lab results and others have minor variances... The Sarin results will never match perfectly given the fact that all of the machines are calibrated slightly different, kept in various states of cleanliness, etc. we find that the machines maintained by the cutters are probably the least accurate because their clients (the dealers) tend not to look at the results as closely as our level of client does... It''s a different degree of scrutiny, the average retailer is just looking for a zero ideal cut rating so that they can say that the diamond is "ideal cut" to a customer who is standing in their store looking at the diamond... Most of our clients can''t see the diamond because they are buying it online and thus they are really looking at the paper to increase the possibility of getting a really beautiful stone... This can be a problem for people buying from virtual dealers who don''t personally evaluate their inventory because in that instance they are relying on the scans provided by the cutter. If you''re looking for accuracy, ask the dealer to source the diamond and provide you with an in depth evaluation that provides you with greater detail than the mere Sarin results.
     
  14. bizgk
    Rough_Rock

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    by bizgk » Feb 7, 2005
    Hi,

    What do you mean by "source the diamond?" My situation is explained above (3rd post from the top I believe).. I bought a princess cut, and the GIA and Sarin/appraisal dimensions vary by about .09mm and .04mm (the Sarin measurements are less than the GIA).

    I am getting a second appraisal, but I figure they will just return the same carat, color, clarity etc. beause they will be looking at the GIA report. The diamond is VVS2, so there is not much to blueprint the diamond.

    Any advice?

    Thanks!
     
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