what''s wrong with this round brilliant?

[RBsearch]

Trying to educate myself a bit more, and would like opinions on this round brilliant from whiteflash. Basically, I am wondering why the ideal scope image looks so odd (sort of jumbled and no arrows structure). But it still gets an AGS Excellent 1 cut score and the standard photo looks decent. Any insights into what this might actually look like in person, and how different from an H&A AGS 0 cut? Thanks!

 

[Kelli]

The cut is not so great. It''s a steep/deep and scores a 4.2 (or maybe 4.3-- I forgot) on the HCA, which you can find in the tools link at the top of the page. Try to find a stone that scores under two. I''d pass on this one, as you can clearly see the ring of light leakage you''d expect from the numbers. I''m sure you could find a better expert selection one, but if you want the very best cut possible, try one of the ACAs. To me, it''s worth that extra money.

 

[:)]

Deep stone, leaking in the middle. The diamond may be slightly rotated in the pics, but not much.

 

[swingirl]

This stone is deep. The desired range is 60–62 (could go up as high as 62.6%)

When WF uses a stock photo it says IMAGE NOT AVAILABLE. The photo for this stone is correctly shown and is not a stock photo. (If they have the real ASET and real Idealscope, they'd also have the real image)

The Expert Selection stone from WF might be nice for the price. But I'd want WF to describe it over the phone and tell me how it compares to their ACAs. Some ES are very nice and others, not so much.

 

[Lorelei]

Date: 1/20/2009 11:10:43 PM
Author:
Deep stone, leaking in the middle. The diamond may be slightly rotated in the pics, but not much.

Ditto, double deep and steep ( depth, pavilion and crown) with what we call the ring of death clearly showing in the Idealscope image.

Here are some numbers you can use as a guide to help you find a well cut round diamond.

depth - 60 - 62% - although my personal preference is to allow up to 62.4%
table - 54- 57%
crown angle - 34- 35 degrees
pavilion angle - 40.6- 41 degrees
girdle - avoid extremes, look for thin to slightly thick, thin to medium etc
polish and symmetry - very good and above

note - with crown and pavilion angles at the shallower ends ( CA 34- PA 40.6) and steeper ( CA 35- PA 41) check to make sure these angles complement in that particular diamond - eyeballs, Idealscope, trusted vendor input - check as appropriate!

From expert John Pollard.

As the above implies, configurations depend on each other. A little give here can still work with a little take there.

With that said, here's a "Cliff's Notes" for staying near Tolkowsky/ideal angles with GIA reports (their numbers are rounded): A crown angle of 34.0, 34.5 or 35.0 is usually safe with a 40.8 pavilion angle. If pavilion angle = 40.6 lean toward a 34.5-35.0 crown. If pavilion angle = 41 lean toward a 34.0-34.5 crown.

GIA "EX" in cut is great at its heart, but it ranges a bit wider than some people prefer, particularly in deep combinations (pavilion > 41 with crown > 35).