Is my shallow cut diamond really lesser than? Featuring a 40.3 pavilion angle.

[sech]

Hi folks.

I realize I may be opening a contentious thread here, but I am curious as to how it's possible for a diamond with a shallow pavilion angle to still perform pretty decently, when everything I have read so far re: cut proportions seems to suggest these numbers are not preferable.
Here I am mostly referring to the "recommended proportion combinations" chart which often floats around here as a general guide.

The pavilion angle on my diamond falls outside the limits of this chart, at 40.3 degrees, and the crown angle is 35.7 degrees, fitting into none of the prescribed recommendations.

Now, I am a very picky person normally, and have been told I have a good eye, even by a jeweler once (ha!) so I am a little baffled as to why I can't seem to find any serious visible flaws with my diamond. I have looked at it in various lighting conditions, and apart from noticing that the stone is clearly more shallow in profile, I feel that I'm looking at an overall well performing diamond. It scintillates and sparkles very nicely in every lighting condition, and is also quite bright. I do not see any off-putting over-obstruction, though of course, I do not have a trained eye for this (I would love to have one of the experts weigh in on this aspect after seeing my linked photos & videos).

So, what am I missing?
I would be grateful to have someone explain this phenomenon to me. My curiousity is absolutely peaked.

This is also my first post on here so please forgive me if I have not linked/attached things properly.

Here is the 360 loupe for my diamond, and the IGI ID is LG628417912.

Thank you in advance for your contributions.

 

[sech]

Hi folks.

I realize I may be opening a contentious thread here, but I am curious as to how it's possible for a diamond with a shallow pavilion angle to still perform pretty decently, when everything I have read so far re: cut proportions seems to suggest these numbers are not preferable.
Here I am mostly referring to the "recommended proportion combinations" chart which often floats around here as a general guide.

The pavilion angle on my diamond falls outside the limits of this chart, at 40.3 degrees, and the crown angle is 35.7 degrees, fitting into none of the prescribed recommendations.

Now, I am a very picky person normally, and have been told I have a good eye, even by a jeweler once (ha!) so I am a little baffled as to why I can't seem to find any serious visible flaws with my diamond. I have looked at it in various lighting conditions, and apart from noticing that the stone is clearly more shallow in profile, I feel that I'm looking at an overall well performing diamond. It scintillates and sparkles very nicely in every lighting condition, and is also quite bright. I do not see any off-putting over-obstruction, though of course, I do not have a trained eye for this (I would love to have one of the experts weigh in on this aspect after seeing my linked photos & videos).

So, what am I missing?
I would be grateful to have someone explain this phenomenon to me. My curiousity is absolutely peaked.

This is also my first post on here so please forgive me if I have not linked/attached things properly.

Here is the 360 loupe for my diamond, and the IGI ID is LG628417912.

Thank you in advance for your contributions.

Videos of the diamond can be seen here in various lighting.

 

[Karl_K]

Not at my pc to look at all the numbers.
35.7ca helps a 40.3pa and combine it with longer lowers(smaller arrows) and the right table size the effects are darker arrows up close that stay somewhat darker at longer distances.
This translates into looking slightly darker at those distances.
With the right combo these effects are very minor.
So the short answer is you lucked into a good combo.
Some combos with 40.3 pavilions have far more issues.

 

[Karl_K]

Got me curious enough to go to my pc, the 56table is perfect for this combo.
It would get the top grade in the new IGI system I helped design.

 

[sech]

Got me curious enough to go to my pc, the 56table is perfect for this combo.
It would get the top grade in the new IGI system I helped design.

Well thank you so much for offering the missing puzzle piece, ha! What a nice surprise.

I am fascinated by everything that encompasses the world of diamond grading and would love to hear more about your new system!

 

[sech]

Got me curious enough to go to my pc, the 56table is perfect for this combo.
It would get the top grade in the new IGI system I helped design.

And now, upon further consideration, this may explain why this shallow cut diamond outperforms a deeper cut diamond I have which does align with the ranges found in the recommended proportions chart I mentioned earlier. I thought that odd in the beginning.

Thank you for taking the time to reply. I appreciate it

 

[Karl_K]

What we did that it is different and why these shallower pavilion diamonds score better than on GIA and AGS systems is mainly viewing distances.
Diamonds look dramatically different at different distances.

GIA is based on viewing diamonds in a grey box at close range by mainly industry folks.
AGS is based on a military standard of 10 inches, which is considered for young people the beginning of the range they can focus on a small object.
What we did is actually looked at how people looked at diamonds on their hand.
We found a distance of 15 inches and longer is much more realistic.
So we made that our primary distance but did take shorter and longer distances into consideration.

 

[sech]

What we did that it is different and why these shallower pavilion diamonds score better than on GIA and AGS systems is mainly viewing distances.
Diamonds look dramatically different at different distances.

GIA is based on viewing diamonds in a grey box at close range by mainly industry folks.
AGS is based on a military standard of 10 inches, which is considered for young people the beginning of the range they can focus on a small object.
What we did is actually looked at how people looked at diamonds on their hand.
We found a distance of 15 inches and longer is much more realistic.
So we made that our primary distance but did take shorter and longer distances into consideration.

I wasn't aware that each of these grading systems are based upon varying viewing distances. Thank you for this insight.

I agree with frequently viewing my diamond at a distance of at least 12 inches. It feels like I'm able to admire the sparkles and flashes of light more completely in that manner, if that makes sense. Particularly in direct lighting. In indirect lighting, I enjoy bringing the diamond much closer up to my face. The arrows are also easier to spot that way, against the bright, white backdrop of the rest of the diamond.

There's one more thing that I've been curious about. I've recently observed that this diamond photographs in a peculiar way; the stone turns very dark (greyish) with mobile flash photography, most noticeably when photographed at closer distances. My other diamond, the one with the deeper cut, photographs white. What is the reason behind this? Could the depth of the cut have something to do with this? Or is it simply a matter of cut grade? Or both? The deeper cut diamond is also smaller, at roughly 0.8ct–perhaps that also plays a role.

 

[Karl_K]

With the flash its the different proportions.
Its an awful way to compare diamonds.

 

[Karl_K]

When someone is looking for a specific effect like dark arrows they are going to move the diamond to what ever distance the arrows look best to them.
That exact distance is not critically important and will vary person to person even for the same diamond and lighting.

 

[Dreamer_D]

Which grading system works for 45yo who can’t see distances or up close anymore

 

[Karl_K]

Which grading system works for 45yo who can’t see distances or up close anymore

HCA is the one I can name without a conflict.
The reading area of bifocals or variables is set to 15 to 20 inches for screens these days vs 12 ish for books before..

 

[kenny]

So, what am I missing? ...

Perhaps what you're missing is a proper comparison ... IOW a diamond with even better light performance to put it next to (IN PERSON) .

There is NOTHING like a side by side comparison.
Ice cream X may be the best you could have ever imaged ........... that is till you taste text ice cream X next to ice cream Y.
Nearly everything is that way.

If you have the funds, or the credit limit, I'd buy an ACA of the same size color and clarity from www.whiteflash.com .
Make sure it comes in one of those temporary clip settings so you can "wear" it ... carefully, but wear it.
I'd carefully wear both, side by side, in many different lighting conditions.

Then decide.
I think this will show you what "you are missing".

WF has a great return policy so if you return it (following their policy) for returns (though I doubt you will) you'd only be out the shipping cost.

If you do this, please come back to this thread and post your impressions.