GIA cut grade clarification

[chitra]

I recently bought a pair of stones, these come with GIA excellant cut grade, but when I see the stats they seem to have only VG grade.

#1 -- Table - 59%, depth 59.7 crown angle - 33 and pav angle 40.8
#2 -- Table - 59% depth 60.3% crown - 33 and pav angle - 40.8

I referred to the GIA cut grading links in pricescope and GIA site here https://www.gia.edu/doc/booklet_cut_estimation_tables_lowres.pdf
Any thoughts on why this is classified as excellant cut and not very good cut?

 

[kenny]

Yes, GIA's so-called top cut grade of Excellent is lax enough to include some proportions that are anything but Excellent.

A search here on PS will reveal many threads about this.

IMO if you want a diamond that has the best light performance, but don't want to get into the technical stuff, get one that AGS has graded AGS 0.
When it comes to reputability, AGS is GIA's main competitor in USA

And if you are looking for a round brilliant shaped diamond, use the HCA to evaluate its cut quality for light performance:

Holloway Cut Advisor | HCA Tool

The HCA Tool uses data from a round brilliant diamond to produce a score that can help you make an estimate regarding the cut quality. Use it here.

www.pricescope.com