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BrillianceScope vs. HCA

Discussion in 'RockyTalky' started by Homer, Jan 11, 2001.

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  1. Homer
    Rough_Rock

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    by Homer » Jan 11, 2001
    Which should I put more emphasis on, a diamond's BrillianceScope results, or the HCA? For example, HCA says 3, BrillianceScope is H2/VH3/H3. Are these readings consistent?
     
    


    


  2. Homer
    Rough_Rock

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    by Homer » Jan 11, 2001
    Leonid,I am curious. I had done the HCA for the first stone you included (the 1.52 H SI1 000)and got a result of 1. You list it at 0.8. Why the difference?
     
  3. pricescope
    Ideal_Rock

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    by pricescope » Jan 11, 2001
    Homer, You are right - I didn't include the culet. Since culet is larger than 1% Garry adds penalties for it.Without culet HCA gives 0.8 for 34.7 crown and 40.5 pavilion angles.
     
  4. pricescope
    Ideal_Rock

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    by pricescope » Jan 11, 2001
    Hi Homer,I think they are consistent. Check this out:1. http://www.goodoldgold.com/148.htm
    BrillianceScope: VH1/VH3/H2
    HCA: 0.8 - Excellent 2. http://www.goodoldgold.com/149.htm
    BrillianceScope: H3/VH2/H1
    HCA: 1.7 - Excellent 3. http://www.goodoldgold.com/183.htm
    BrillianceScope: H/VH/VH
    HCA: 2.8 - Very Good 4. http://www.goodoldgold.com/155.htm
    BrillianceScope H, VH, H
    HCA: 3 - Very Good5. http://www.goodoldgold.com/184.htm
    BrillianceScope: H1/VH1/M2
    HCA: 3.5 - Very Good 6. http://www.goodoldgold.com/newpage35.htm
    BrillianceScope: H1/H3/M2
    HCA: 3.7 - Very Good All these stones are AGS0.Although B’scope and HCA are different animals you can see that the lower overall b’scope readings the more penalties the stone gets on HCA.The stone you are asking about is the one with 35.1 deg crown and 40.9 deg pavilion angles. Although it is not the worst AGS0 but it has quite a steep crown and a bit deep pavilion. On AGA system it would only get 2A grade - International Fine Cut, not ideal ( www.gemappraisers.com ).On the MSU charts you can easily see how brilliance gets less than 1 for this combination of crown and pavilion angles: http://www.gemology.addr.com/cut/english/podrobno_2.htm .Does it make sense?
     
    


    


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