HCA Graph question

kmans · May 24, 2007

If a GIA cert diamond has its "X" on the HCA graph within the AGS specs of ideal cut(represented by white line) and also within the GIA excellent specs(green dotted line). Does this mean that, if this diamond was to be graded by AGS then it would be an ideal cut diamond?

Just to add, If the stone has excellent symmetry and polish. Then would this be a triple 000 diamond??/

Not sure if i am making sense here...but wanted some clarity on what exactly the white line/green dotted line mean exactly

JohnQuixote · May 24, 2007

Date: 5/24/2007 8:58:57 PM
Author:kmans
If a GIA cert diamond has its ''X'' on the HCA graph within the AGS specs of ideal cut(represented by white line) and also within the GIA excellent specs(green dotted line). Does this mean that, if this diamond was to be graded by AGS then it would be an ideal cut diamond?

The AGS outline is predictive only. The diamond would need to be sent to AGS for scanning/ray-tracing to see if it would actually earn the Ideal light performance grade - but if its near the heart of the indicated AGS area it''s likely.

More here: https://www.pricescope.com/community/threads/ags-2-or-ags-0-the-candidate-vs-parametric-grades.58088/

Just to add, If the stone has excellent symmetry and polish. Then would this be a triple 000 diamond??/

Not sure if i am making sense here...but wanted some clarity on what exactly the white line/green dotted line mean exactly

The AGS ''Ideal'' grade in polish/symmetry is touted as a bit stricter than GIA''s Excellent. Some debate that. Regardless, there is no visible difference between VG, EX and Ideal finish.

There is simply no way to know if a diamond will be AGS Ideal without sending it to the AGS for grading. However, if you''re just seeking ''bragging rights'' among your friends, GIA triple EX diamonds that fall at the heart of traditional ''ideal'' proportions are pretty likely to earn the AGS laurels too.