a question about GIA and AGSL

[swl]

From what I understand, AGSL has a stricter range for Ideal 0 than GIA excellent. If both stones score 1.2 on the HCA, does it assume they are similarly cut, and have similarly performance?

 

[Lorelei]

Date: 7/2/2009 10:08:38 PM
Author:swl
From what I understand, AGSL has a stricter range for Ideal 0 than GIA excellent. If both stones score 1.2 on the HCA, does it assume they are similarly cut, and have similarly performance?

The HCA is for elimination not selection, it cannot physically see the diamond and the results are based on very limited information, also with the forced rounding of GIA angles this can further distort the results, also the HCA does not take into account star and lower girdle facets which can alter the character of each diamond. To really get a good idea on how to compare 2 diamonds which score similarly on the HCA, Idealscope and or ASET images are needed.

 

[Garry H (Cut Nut)]

Potentially both the GIA and AGS with HCA 1.2 are excellent stones in round shapes.
AGS 0 has very strict polish and symmetry standards, but it is unlikely that a stone with GIA VG VG and all the other same attributes and proportions would loook different.
Eyes - yours if you have some practice, a trusted vendor or an appraiser will help if you want better than usual cut quality and beauty.