New GIA cut-grading-system launch Jan 2006

[Rhino]

Ok... playing around today a lil with the new GIA Cut Calculator. I''m finding many positives and also some negatives. One that is really throwing me for a loop is this ...

Here are known poop proportions for an ideal cut and the stone DOES NOT get a GIA Grade 1. Hooray for GIA!

 

[Rhino]

Here''s the simullated ls results. Too much leakage under the table. 35 degree crown angles, 41.2 pavilion, 56 table sucks for an ideal cut.

 

[Rhino]

Here''s the disturbing part...

Change the table to 60% and the stone gets an "Excellent"!!!

 

[Rhino]

When diamonds have extraneous leakage under the table, *smaller tables* IF ANYTHING are best. When you increase table size you open up the diamond to even more leakage. Here''s resultant ls image.