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Will Faceted Girdle cause 'leakage' to H&A Diamond?

Discussion in 'RockyTalky' started by Evelynleetc, Jun 10, 2001.

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  1. Evelynleetc
    Rough_Rock

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    by Evelynleetc » Jun 10, 2001
    Hi! I recently bought a GIA certified 1.38 F VVS2 Round Brilliant.It was suppose to be a H&A Diamond. However, I saw a consistent whitish ring of light all around it. (The h&A's were all well formed). Was told that this was the result of the faceted girdle and not a leakage. The girdle thickness was thin to slightly thick.Would appreciate your comments.
     
    


    


  2. Evelynleetc
    Rough_Rock

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    by Evelynleetc » Jun 10, 2001
    Just read somewhere about this Holloway cut advisor.... What's that??Anybody have any idea on the diff between the production and the prototype Ideal scope?Thanks a lot!!
     
  3. pricescope
    Ideal_Rock

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    by pricescope » Jun 11, 2001
    Hi Evelynleetc,Faceted and polished girdle does let the light enter the diamond. It might be a reason of the effect you observe.In what lightening conditions do you see this effect? Is diamond illuminated from the pavilion? Do you see the whitish ring on the diamond or surrounded surface?Light leakage means the light entered diamond from the table or crown facets doesn't returns back and exits (leaks) through pavilion or girdle. The Ideal-Scope helps visualize the light leakage (see www.pricescope.com/idealscope_indx.asp )Usually every diamond leak light in small V-shape areas around the girdle: [​IMG] Generally speaking H&A symmetry itself doesn't guarantee that diamond is leakage free. Here is an example when H&A diamond has more light leakage than the one with non-ideal symmetry. [​IMG] Do you know crown and pavilion angles for your diamond?
     
  4. pricescope
    Ideal_Rock

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    by pricescope » Jun 11, 2001
    Evelynleetc,The idea of the Holloway Cut Adviser (HCA) is evaluating diamond as alternative to AGS system. In the tutorial you can see why AGS cut grading system allows light leaking diamonds to be graded as ideal and leaving many beautiful diamonds outside.HCA system is based on 16+ years of visual diamond observations using Firescope and computer modeling by DiamCalc software. Check out www.diamond-cut.com.au and www.cutstudy.com/cut for more info.There is no principle difference between prototype and production idea-scope models. They both use the same magnifier but the production model has a neat fitting injection molded pink reflector instead of the card that you have in your prototype model.
     
    


    


  5. barry
    Shiny_Rock

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    by barry » Jun 11, 2001
    The whiteish light you see is NOT
    from the faceted girdle, but
    indicative of the cut quality.H&A does not necessarily guarantee
    a stone that is light-leak proof.I'd look at this diamond with a
    firescope.Barry www.superbcert.com ------------------
    barry
     
  6. Evelynleetc
    Rough_Rock

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    by Evelynleetc » Jun 11, 2001
    Thanks Barry and Leonid.This GIA diamond did not have a Sarin report, so I'm afraid that I do not know the crown and pavilion angles. All I know is that it measures 7.12 - 7.17 x 4.45mm and the depth is 62.3%, Table 56% , Excellent Polish and VG Symmetry. No Fluorescence.I was given this Blue scope thingie to look at the H&A. Fould that there was this triangle whitish light all around the diamond. There was no other whitish triangles around the diamond. Is it a leak?I sincerely hope not. Wonder how much should I have paid for it?
     
  7. pricescope
    Ideal_Rock

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    by pricescope » Jun 11, 2001
    H&A viewer doesn't show light leakage. It is only shows optical symmetry of the stone. If you see the whitish in the H&A viewer, it cannot be a light leakage.Unfortunately, table size and total depth on GIA certifficate are not enough to evaluate the cut.
     
  8. Evelynleetc
    Rough_Rock

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    by Evelynleetc » Jun 11, 2001
    Oh! You mean that the h&A acope and the Fire scope are 2 diff things?Cool!! Guess that i got to lay my hands on one then. Thanks.
     
  9. pricescope
    Ideal_Rock

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    by pricescope » Jun 11, 2001
    Yes, h&A acope and the Firescope are 2 diff things
     
  10. Garry H (Cut Nut)
    Super_Ideal_Rock
    Trade

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    by Garry H (Cut Nut) » Jun 11, 2001
    Leonid is showing you images from a more sophisticated 'toy' - the ideal-scope.
    The H&A viewer gives no real assistance with light loss or return.
    You might like to buy one of the prototypes at www.ideal-scope.com for only $10 +P+P
    then you can tell us how your stone performsI buy thousands of diamonds a year, but would not buy a single diamond if you stole my ideal-scope - it is the best gadget!
    garry holloway
     
    


    


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