Question on GIA XXX

[SSam]

Hi everyone,

What is the maximum girdle thickness allowed to achieve GIA excelent cut in percentage of total height? Also could anybody advise me on the maximum deviation allowed between individual crown and pavilion angles, is this 0.6%? I am having problems finding specific figures on the GIA website.

Thanks!

 

[JulieN]

GIA EX grades for girdle are Thin, Med, and Slt Thick. GIA doesn't give depth as a percentage on their reports.

I've never heard of the .6% deviation.

 

[SSam]

The girdle categories are the only ones that I seem to be able to find but there must be categories as a percentage.
The 0.6% deviation is the maximum difference between different crown or pavillion facets. This data used to be freely available but I am having difficulties finding it. Anyone have any idea?

 

[JulieN]

There are girdle categories as percentages... but GIA uses depth (in mm) to give girdle thickness (more or less.) Two different systems.

 

[JulieN]

Ok, here is, (I guess) the definitive answer to your girdle question: http://www.gis.net/~adamas/gir1.gif

 

[SSam]

Date: 6/6/2006 7:56:54 AM
Author: JulieN
Ok, here is, (I guess) the definitive answer to your girdle question: http://www.gis.net/~adamas/gir1.gif

Thanks Julie!

So you got the percentages merely by calculating the percentage based on mm measurements?