Your color grading system looks nearly identical to the system used
by GIA. The main difference is that they use a written modifier and
capitalization for the hue, i.e., slightly bluish Green (sl. bG) vs.
bluish Green (str. bG) and you use a + and - sign Slightly Bluish
Green (-BG) vs. Strongly Bluish Green (+BG).
But my CDS also reveals saturation and tone. The GIA system uses
separate tables for saturation and tone.
The one hue description I did not see in your system is a 50/50 split
of hues, Blue Green/Green Blue. In this hue combination, neither
color is the dominant like in the hue bluish green, where green is
I haven’t been around enough to see an absolutely 50/50 split. What
gems would it apply to?
Why not use the GIA system?
As I said in my original e-mail. GIA has copyrighted their system
and does not distribute their system freely. If I use it I would be
violating their copyright.
It seems similar enough plus more flexibility with the hue
description. The tone and saturation descriptions are nearly
identical (1,2,3 etc.)
Again, its a matter of “free usage,” and I personally feel that 5
divisions are difficult enough to segregate. AIGS uses 6 on tone and
Also, although I have never seen a GIA handbook on color stone
grading, I have never heard mention that GIA uses percentage of
brilliance in grading. IMHO, color is first, brilliancy (internal
luster) is second. Brialliancy flashes tell a lot. That is where
you actually see the hue and saturation. Brilliancy % and “quality
of brilliance” (i.e. clean or fuzzy) will also tell you a lot about
"make" and inclusions.
Also, as I stated, my CDS aqnd grading system aren’t carved in
Thanks for your evaluation. I appreciate your comments.