GIA SI1 ex/ex/ex - Stone too deep?

[the1kayladawn]

My now fiance proposed with a 1.20 ct GIA ex/ex/ex Si1 G stone.
I have not been able to see any inclusions with the naked eye, and find the color to be great as well. And as far as he thought, going ex/ex/ex meant a surefire beautiful stone.

A friend with more diamond knowledge than myself or fiance commented they didn't care for the diamond because it's too deep and that we should return it......

I am attaching the certificate and hope that some of you can help me out. I know it looks like the inclusion is right in the middle but I couldn't see it even with a loupe.

 

[drk14]

Your certificate is difficult to read, but I think the measurements are as follows:
62.8% depth, 56% table, 33.5° crown angle, 41.6° pavilion angle

This yields an HCA score of 4.9.

 

[Gypsy]

Yes. And the angles and proportions aren't good.

The entire purpose of faceting a diamond is to reflect light.
How well or how poorly a diamond does this determines how beautiful it is.
How well a diamond performs is determined by the angles and cutting. This is why we say cut is king.
No other factor: not color, not clarity has as much of an impact on the appearance of a diamond as its cut. An ideal H will out white a poorly cut F. And GIA Ex is not enough. And you must stick to GIA and AGS only. EGL is a bad option: [URL='https://www.pricescope.com/community/threads/egl-certification-are-any-of-them-ok.142863/']https://www.pricescope.com/community/threads/egl-certification-are-any-of-them-ok.142863/[/URL]
So how to we ensure that we have the right angles and cutting to get the light performance we want?
https://www.pricescope.com/wiki/diamonds/diamond-cut
Well one method is to start with a GIA Ex, and then apply the HCA to it. YOU DO NOT USE HCA for AGS0 stones.
https://www.pricescope.com/wiki/diamonds/holloway-cut-advisor
The HCA is a rejection tool. Not a selection tool. It uses 4 data points to make a rudimentary call on how the diamond may perform.
If the diamond passes then you know that you are in the right zone in terms of angles for light performance. Under 2 is a pass. Under 2.5-2.1 is a maybe. 2.6 and over is a no. No score 2 and under is better than any other.
Is that enough? Not really.
So what you need is a way to check actual light performance of your actual stone.
That's what an idealscope image does. https://www.pricescope.com/wiki/diamonds/firescope-idealscope
It shows you how and wear your diamond is reflecting light, how well it is going at it, and where you are losing light return. That is why you won't see us recommending Blue Nile, as they do not provide idealscope images for their diamonds. BGD, James Allen, GOG, HPD, ERD and WF do.

The Idealscope is the 'selection tool'. Not the HCA.
So yes, with a GIA stone you need the idealscope images. Or you can buy an idealscope yourself and take it in to the jeweler you are working with to check the stones yourself. Or if you have a good return policy (full refund minimum 7 days) then you can buy the idealscope, buy the stone, and do it at home.


Now if you want to skip all that... stick to AGS0 stones and then all you have to do is pick color and clarity and you know you have a great performing diamond. Because AGS has already done the checking for you. That's why they trade at a premium.

 

[krisjon]

That stone might be an eye clean SI1/G color, but it's definitely far from an ideal cut despite the GIA triple EX grading. It's the peril of the wide cut parameters that can still make GIA EX. It favors the diamond cutters more than the customers. There are some great GIA EX stones out there, but you have to pick them carefully by the angles/proportions at the minimum - and then with ASET and/or Idealscope images, as well as seeing it in person.