GIA vs. AGS certification

[brooklyngirl]

I''m looking for an ideal cut RB, and I''ve come upon many diamonds that are graded by GIA as ideal cut. I have read that GIA doesn''t really grade cut well, and that is the most important thing to me when purchasing a diamond. What do you folks think about GIA ideal cut graded diamonds? What about GIA ideal/spready grading?

Thanks!

 

[pyle112]

This tutorial describes the nomenclature used by the different grading laboratories. I think conventional wisdom here says that GIA and AGS graded diamonds are most trusted. GIA does not have ideal or ideal spready.

edit: for more information then you'll ever need check out Rhino's tutorial http://www.goodoldgold.com/4Cs/NewCutGrading/
and the summary section of said site
http://www.goodoldgold.com/4Cs/NewCutGrading/CutGradingFinalThoughts/