Round Brilliant Crown/Pavilion Angles

[ms21]

Hi All,

Ive recently looked at a 1.5ct diamond that had a crown angle of 36.5 and a pavilion angle of 41.0. The table is 57% and depth is 62.3%

I understand that that is out of the generally recommended range that I've seen on this site, but was wondering how the larger crown would effect the overall look of the diamond. Would this create either a nailhead or a fish-eye effect? Or just overall isnt as bright as others with more ideal proportions?

Can you please assist?

Thank you!

 

[Karl_K]

No it would not create a fisheye or nailhead but the predicted ags cut grade of such a diamond is 3-4 depending on specifics and rounding.
Diamcalc predicts a 17% reduction in brightness under the table face up again depending on specifics could be slightly better or slightly worse.
Was it gia graded?
The gia numbers are grossly rounded and that could make it slightly better or slightly worse so at best this is a guess.
An ideal cut runs .97 to 1.0.

 

[ms21]

Thank you for the response and feedback! I really appreciate it.

Yes, I am actually looking at two stones at the moment and both are GIA certified - and both have larger-than-ideal crown angles.

1166302524 and 2178670690 are the two GIA numbers for the stones.

1166302524 is rated triple excellent, and 2178670690 is rated VG X VG, however it appears that there may not be a very large difference between the two based on HCA proportions.

Please let me know if you have any more feedback now that you have GIA information.

Thanks!

 

[Karl_K]

Within the gia rounding there is a chance that 1166302524 would be nice but not what a serious cut nut would consider the very top end.
Many Tiffany diamonds are in that general range.
However the gia numbers are not accurate enough to tell for sure.

 

[ms21]

OK thanks. And as far as 2178670690? Would you say this isnt worth it?

 

[Karl_K]

OK thanks. And as far as 2178670690? Would you say this isnt worth it?

It is not a diamond I would consider.