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Importance Of Depth, Polish, Symmetry For Cushions


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Hello Forum,


I'm going to be purchasing a cushion-cut diamond from a reputable whole seller in the extremely near future. One of the stones I've been eyeing is beautiful, but I'm concerned about its depth. Here are the relevant statistics:


Size: 1.52 c

Color: F

Clarity: VS2

Table: 52.0%

Depth: 72.1%

Dimensions: 7.00 mm x 6.34 mm x 4.57 mm

Symmetry: Good

Polish: Very Good

Price: ~12k


I know the most important thing is the the visual appearance of the stone, but I'm a numbers guy and don't really have a good eye for this kind of thing. I've read that the depth "should" be less than 70%, and because the most important feature for me is the overall cut and brilliance of the stone, I'm concerned about this. So I have a few questions:


*Is a depth of 72% going to adversely affect the radiance or brilliance of the diamond?

*What about "good" symmetry, versus "excellent" symmetry? How does "good" polish compare to "excellent" polish? What about variance in the thickness of the girdle? Do these things really matter once the stone is set? (In case it's relevant, I'm purchasing a halo setting).

*I want a stone that is more square than rectangular. The above has a length/width ratio of around 1.06; the one below has a ratio of about 1.10. I was told by one of the merchants that a halo setting will help "hide" the elongation, so I have a bit more leeway here than I would with different settings. Is this true?


The other stone I'm considering is a cushion modified brilliant with some different specs:

Size: 1.52 C

Color: G

Clarity: VS2

Polish: Excellent

Symmetry: Excellent

Dimensions: 6.62 mm x 6.22 mm x 4.22 mm

Girdle: Medium to Very Thick

Price: ~13K


Note that this is 8% more expensive despite the downgrade in color. I don't know if this is because it's somehow more beautiful than the former, or if it's just because it has XX in polish and symmetry, and that these are merely rarity measurements that don't really affect the appearance of the diamond.


The stones are held by different merchants so I can't compare them side-by-side. Any suggestions would be greatly appreciated. Thank you.


(Both stones are GIA and also boast no fluorescence or culet).



Edited by cushionman
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Hi Cushionman;


Fancy shapes are very difficult to evaluate simply on the numbers. In spite of what you've read on the Internet, the fact is that various combinations of "numbers" can result in a face up sparkly diamond. Buy the diamond, not the "numbers" on the lab grading report.


Your focus should be to work with an experienced diamond vendor that can personally evaluate the diamonds and provide you with photos, light performance analysis, and an accurate verbal description of how the diamond visually presents.

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If they are selling to you, they are a retailer, no matter what they call themselves. In any case, no-one "expects" bargaining, but no-one is going to turn you down.


On your previous questions re: symmetry and polish. They are secondary factors, and scores of "good" and above are fine. Price differences between "good" and "excellent" will be there, but will be minor (a few % points).

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I agree that if they are selling the public, they are not wholesale. Cushion cuts have very different looks depending on the faceting of the stone which you won't be able to see from the lab report. Make sure they show you the stone or stones before you purchase it. I have some clients that prefer the larger bolder facets more reminiscent of the older cuts, and others that like the modern brillliant cushion cut looks. Work with a vendor that can help you decide which stone and look can fit your buget. Make sure you get a GIA lab report on the diamond as well.

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