Holloway Cut Advisor giving inconsistent scores of 1.5-3.9 for same stone! Comments on this cut gre

[Panda]

I have placed a deposit on the following diamond, and I would appreciate feedback on the quality of the cut. Depending upon which cut numbers I plug into the Holloway Cut Advisor, I get scores ranging from *1.5* to *3.9*!!

Two issues that have made the decision more complicated are:
1 - The Megascope and the GIA cert don''t perfectly agree.
2 - I can''t tell what effect the thickish girdle has.


Size: 0.90ct
Color: D
Clarity: VS1
Fluorescence: None

Dimensions: 6.10x6.16x3.83 (Megascope) or 6.09x6.14x3.85 (GIA)
Depth: 62.5% (Megascope) or 63.0% (GIA)
*Table*: 56.9 [56.6-57.2] (Megascope) or 58% (GIA)
Crown Angle: 35.5 (35.3-35. (Megascope)
Crown Height: 15.2% (15.0-15.4) (Megascope)
Pavil Angle: 40.6 (40.5 - 40.7) (Megascope)
Pavil Depth: 42.9% (42.4 - 43.2) (Megascope)
*Culet*: 0.7 (Megascope) or None (GIA)
*Girdle*: 2.5% (1.9-3.7) (Megascope) or Medium to Thick, Faceted (GIA)
Polish: Excellent
Symmetry: Very good

Note: when viewed with a H&A viewer, it looks barely distinguishable from a branded H&A

Holloway cut advisor scores:
Based on the Megascope angles, it is 1.5: Ex/Ex/Ex/Vg
Based on the Megascope %s, it is 2.4: Vg/Vg/Vg/Vg
Based on the GIA (where available) angles, it is 1.6: Vg/Ex/Ex/Gd
Based on the GIA (where available) and %s, it is 3.9: Gd/Vg/Gd/Gd

As a related question, inspection by a jeweler suggests that the diamond has significant graining. Will this have any effect on how people see it at a distance?

Finally, I won''t be able to get an ideal-scope in time to make this purchase. Are there any other suggestions for getting a sense of light-loss?

Many, many thanks for any thoughts.

 

[elmo]

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On 10/2/2004 7:03:16 AM Panda wrote:


Based on the GIA (where available) angles, it is 1.6: Vg/Ex/Ex/Gd

Based on the GIA (where available) and %s, it is 3.9: Gd/Vg/Gd/Gd
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Did the supplier call the GIA and get the GIA's crown and pavilion info? If so you didn't post them. Unless this is the case, these two numbers are without basis.

Probably because of the girdle, this stone has the spread of a nice ideal in the low-mid 80s. At 90 points there is usually an additional premium per carat. Maybe this is factored into the price, maybe not.

 

[pricescope]

When you enter crown and pavilion depth %, HCA translates them into angles using simple trigonometry. The fact that you're getting different results tells that there is a measurement error and reported depth % do not match the angles.

If you would add pavilion, crown and girdle, you'll get only 60.6%. That shows that depth %'s are not accurate.

Use angles instead.

There is actually rater big difference between GIA and Megascope numbers: 58% and 63.0% vs 56.9% and 62.5%.

If GIA measured depth accurately, the diamond might be a bit deep.

 

[Garry H (Cut Nut)]

Guess why it says use angles