Color Grade--GIA vs. AGS

[gemnewbie]

I was speaking to a reliable appraiser today, who told me that AGS is very often off by one color grade, compared to GIA. He also indicated that, while the AGS cut grade standard used to be tougher than GIA, in recent times GIA has pretty much caught up. Finally, he said that, because of these factors, GIA stones generally sell at a premium compared to comparable AGS diamonds. Your comments would be most appreciated--especially from those of you who are "independent", ie: aren''t big sellers or suppliers of AGS stones.

 

[Regular Guy]

Well, you''ve got a few things going here. I''ll jump in with impressions:

Date: 10/28/2009 3:49:16 PM
Author:gemnewbie
I was speaking to a reliable appraiser today, who told me that AGS is very often off by one color grade, compared to GIA. He also indicated that, while the AGS cut grade standard used to be tougher than GIA, in recent times GIA has pretty much caught up.

* A couple of things going here. My impression from small talk on this board right now is that AGS is mostly similar in color grading to GIA, but if anything, may be slightly more stringent. But, to say AGS has caught up or behind doesn''t make practical sense, since GIA is sort of considered the author/authority on color, so what they say goes...i.e. if it is substantively different in any than GIA...it is sort of that much wrong...if getting it "accurate" is your target

Finally, he said that, because of these factors, GIA stones generally sell at a premium compared to comparable AGS diamonds.

*Seems more clearly not true. AGS sells as a modest premium to GIA. See notes on this further below...

Your comments would be most appreciated--especially from those of you who are ''independent'', ie: aren''t big sellers or suppliers of AGS stones.

The reason for the premium AGS earns over GIA is not color assessment, but cut, where it''s regarded that AGS''s rendering of a more premium cut is more rigorous and precise, and the market I do think validates this impression.

 

[stone-cold11]

Yap, stones with AGS0 cut grade definitely sells at a premium compared to GIA Ex cut stone. Just do a search using the pricescope your diamond link above.

 

[AshNZ]

Have GIA sorted out there fluorescent lighting debarcle or do they still grade with some UV light?

Ash

 

[ct-appr]

It was only a few years ago that GIA would even put a cut grade on their reports. AGS has always been big on the cut grade. I think GIA has caught up to AGS to some degree, but the AGS report still commands a premium.

FYI-Now we have tools like the ASET, Idealscope and H&A scope to visually analyze the cut of the stone. Many vendor websites have these images readily available. Remember, the cut of the diamond alone, with the other factors held constant, can affect the price of the stone up to 70%.