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HCA results are for Medium Girdle?

Discussion in 'RockyTalky' started by gr8foolishness, Jan 26, 2002.

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  1. gr8foolishness
    Rough_Rock

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    by gr8foolishness » Jan 26, 2002
    How much do the HCA results vary based on a thin or thick girdle? And what range of measurements constitutes thin/medium/thick based on the measurements given on a Sarin report or AGS certificate-these measurements are from valley to valley-correct? :read:
     
    


    


  2. Garry H (Cut Nut)
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    by Garry H (Cut Nut) » Jan 26, 2002
    Girdle has a very minor effect on beauty and a major effect on spread. The latter is taken into account a little - we will have a fee based service soon that does more with girdle.
    Thicker girdles can sometimes improve diamond beauty and sometimes reduce it - it is non obvious.
     
  3. gr8foolishness
    Rough_Rock

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    by gr8foolishness » Jan 26, 2002
    Thanks for your reply-although I still have a couple of questions. I read your tutorial on spread, I understand the concept, but how is it calculated? And what measurement constitutes a thin, medium, and thick girdle-and is that measurement from valley to valley or the thinnest and thickest part of the girdle?:confused:
     
  4. Garry H (Cut Nut)
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    by Garry H (Cut Nut) » Jan 26, 2002
    thin bit to thin bit
    different labs use different methods
    Marty haske has a site that shows it all
    it is more complex than you probably need to know about
    medium to slightly thick is all you really need to know I think
     
    


    


  5. pricescope
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  6. gr8foolishness
    Rough_Rock

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    by gr8foolishness » Jan 27, 2002
    Thanks again-so it seems that the GIA says girdle thickness is relative to the size of the stone-yet then there is actually a constant and you can do the math and figure out whether the girdle is thin, medium, thick-my main question is the math-the girdle number on a Sarin report is listed as a % of the diameter of the diamond? If I take the girdle measurement of 1.4% on a diamond that is 5.71mm in diameter, the girdle would be .07994mm-this doesn't make sense with the graphs in the article-what am I doing wrong? Help!:confused:
     
  7. Garry H (Cut Nut)
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    by Garry H (Cut Nut) » Jan 27, 2002
    Gr8 are you buying certified diamonds or about to start your own lab?
    These decisions are made differently by different labs with different rules etc.
    I think you should communicaate directly with the labs because I may well wrongly advise you on such very specific questions.
    if your questions concern the purchase of a diamond then I really feel you are in way to deep in your line of enquiry. If that is the case then you are possibly going to end up buying an 8* and you will be devastated when you see the girdle.
    Garry
     
  8. gr8foolishness
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    by gr8foolishness » Jan 27, 2002
    Maybe I am not phrasing my question correctly-what constitues a medium girdle-i.e.since you can't use %'s to determine a girdle rating(thin,medium,thick)is there a range of measurement .5mm, 1mm, 1.5mm, etc. that would be medium?
     
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