GIA Ex/Ex..What''s a good estimate on the angles?

[stujin]

I have a GIA Ex/Ex stone, but do not have any SARIN data to plug the stone into the HCA tool, etc. I was wondering if there is a simple way to get an idea of where the stone will lay on the HCA chart without having the angles? I thought I read one time that all GIA ex/ex will fall within certain angle percentages? Is this correct? I may just be dreaming though. Thanks for the help!

 

[joycer]

Without the crown and pavillion angles listed, you won''t be able to use the HCA. GIA reports only comment when crown angles are less than 30 degrees or more than 35 degrees for round brilliants. So if there''s no comment about the crown angles then they fall in 30-35 degrees, but that doesn''t really narrow down anything. If you have a reasonable depth and table % then it might be "safe" to assume the rest of the proportions are ideal also, but then again, you''d still be assuming.

-joycer

 

[Mara]

nope you can't estimate angles at all nor can you assume cut will be great because it's an EX/EX on polish and symmetry, so please get a sarin and go from there.