Is AGS getting too lenient with cut grade?

[Laila619]

What is going on?

This diamond http://www.jamesallen.com/diamonds/G-SI2-Ideal-Cut-Round-Diamond-1480286.asp was given an AGS ideal cut grade, but it's absolutely a steep deep, and it has the ring of death in the middle, which is easily visible. I didn't need to run it through the HCA to know it would score poorly, but sure enough it scores 4.5. That's only one example. I'm seeing more and more diamonds given an AGS ideal cut grade lately, but they are leaky and have overly steep pav angles paired with steep crowns. We'd expect this with GIA since their excellent cut grade encompasses a wide variety, but with AGS?! Can any experts explain what the deal is? Is AGS getting more lax?

 

[0-0-0]

I don't think it looks all the bad based on the image and CG ASET, but it's certainly not great by PS standards. I think the common argument for giving stones with slight under table leakage the top cut grade is that the leakage is not as noticeable when you look at the stone with both eyes. Not really sure if AGS is getting more lenient with the cut grade, but I think it's likely that cutters are getting better at targeting the minimum baseline to get the AGS 0 cut grade over time, and as a result we see more marginal AGS 0 cuts available.

 

[Laila619]

I don't think it looks all the bad based on the image and CG ASET, but it's certainly not great by PS standards. I think the common argument for giving stones with slight under table leakage the top cut grade is that the leakage is not as noticeable when you look at the stone with both eyes. Not really sure if AGS is getting more lenient with the cut grade, but I think it's likely that cutters are getting better at targeting the minimum baseline to get the AGS 0 cut grade over time, and as a result we see more marginal AGS 0 cuts available.

Hmm, yeah, that does make sense I suppose. I thought AGS had tighter cut requirements than the above stone though.

 

[missy]

I don't think it looks all the bad based on the image and CG ASET, but it's certainly not great by PS standards. I think the common argument for giving stones with slight under table leakage the top cut grade is that the leakage is not as noticeable when you look at the stone with both eyes. Not really sure if AGS is getting more lenient with the cut grade, but I think it's likely that cutters are getting better at targeting the minimum baseline to get the AGS 0 cut grade over time, and as a result we see more marginal AGS 0 cuts available.

Hmm, yeah, that does make sense I suppose. I thought AGS had tighter cut requirements than the above stone though.

I thought so as well. That's disappointing because I feel that generally, AGS is softer on color than GIA, but I had always thought they were tougher on cut. Maybe not so anymore...

 

[TRIALnERROR]

What about leniency with regard to color grading? I would expect two color grade difference between GIA vs. EGL, but not from AGS. Is AGS generally considered soft on grading color? A fellow PS'r made the following discovery, GIA VS2 K vs. AGS SI1 I:

AGS report:
http://www.jamesallen.com/AGS-Diamond-Certificate/1445793/I-SI1-Ideal-Cut-1.27-Carat-Round-Diamond.JPG

GIA report:
http://www.jamesallen.com/diam/400C/RO80742cer.jpg
https://myapps.gia.edu/ReportCheckPortal/getReportData.do?&reportno=2141120652&weight=1.27

ETA: Just saw Missy's comment, so I guess this is considered the norm and not the exception.

 

[Laila619]

What about leniency with regard to color grading? I would expect two color grade difference between GIA vs. EGL, but not from AGS. Is AGS generally considered soft on grading color? A fellow PS'r made the following discovery, GIA VS2 K vs. AGS SI1 I:

AGS report:
http://www.jamesallen.com/AGS-Diamond-Certificate/1445793/I-SI1-Ideal-Cut-1.27-Carat-Round-Diamond.JPG

GIA report:
http://www.jamesallen.com/diam/400C/RO80742cer.jpg
https://myapps.gia.edu/ReportCheckPortal/getReportData.do?&reportno=2141120652&weight=1.27

ETA: Just saw Missy's comment, so I guess this is considered the norm and not the exception.

Yes, I once owned an AGS H color, and it looked noticeably tinted to my eye. I still to this day think it might have been a GIA J or I.

ETA: [URL='https://www.pricescope.com/community/threads/i-had-an-i-diamond-appraised-today-and-was-told-that-it-was-a-k.55486/']https://www.pricescope.com/community/threads/i-had-an-i-diamond-appraised-today-and-was-told-that-it-was-a-k.55486/[/URL] Harriet, a long-time poster on PS, experienced this same thing. She bought an I and it appraised as a K.

 

[E B]

ETA: Just saw Missy's comment, so I guess this is considered the norm and not the exception.

Two grades certainly can't be the norm with AGS' (general) reputation, can it?

 

[missy]

Hi trialnerror,
I cannot speak as to what others think. This is my perception only. When I compare an AGS G to a GIA G I feel that AGS is about 1 color grade softer and the AGS G is more like an H (GIA H). To my eyes and I am generalizing. There are higher G's than others if you KWIM but basically I think AGS is soft on color grades as compared to GIA. I am sure there are many here who would disagree. However, I always thought they were tougher on cut grades than GIA as evidenced by all the GIA excellent cuts that really aren't whereas AGS ideal always had ideal light return. Now I wonder.

 

[0-0-0]

On color and clarity, this was Paul's impression from a year ago.

[URL='https://www.pricescope.com/community/threads/ags-vs-gia-color-grades.158302/#p2878903']https://www.pricescope.com/community/threads/ags-vs-gia-color-grades.158302/#p2878903[/URL]

We have, aside from our own brand, also unbranded production of the same quality for other retailers, and they often prefer to use GIA as a lab. As such, this also gives me a general idea about the small differences in grading between the labs.

In general, they are on par, but that does not mean that they will grade exactly the same. My feeling and experience are roughly the following:
- In colour, GIA is a tad stricter than AGS, I estimate about one tenth of a grade.
- In clarity, it is the other way around and the difference a bit higher, I would say AGS about three tenths of a grade stricter.
- In comparison, HRD, I regard them about two tenths of a grade stricter in colour than GIA, but about half a grade less strict in clarity.

A consumer thus would like to have the colour graded by HRD and the clarity by AGS, and a seller would probably prefer the colour graded by AGS and the clarity by HRD. However, both are combined on one report, so that does not work.

If we look value-wise, comparing GIA to AGS, the slightly stricter clarity has more effect than the colour, so the total AGS-grade on colour and clarity would be a bit more valuable. This also reflects in the small premiums for AGS-reports compared to GIA.

 

[InnaR]

I noticed that AGS color grade is more lenient on at least four stones.
In 2009 I bought three stone ACA ring from Whiteflash (.8, .3, .3) All three are graded AGS I VS2-SI (as I think all of their ACA diamonds). Set in white gold. The yellow is very apparent in all three stones. So while the cut is exceptional and all three produce enormous amount of fire and light, the yellow tint was immediately noticed by both me and my mom (I bought her this ring as a present).
Similarly I noticed and posted couple of times my reaction to two AVCs. Both graded by AGS - first L, than J. I was surprised at how much color both stones showed.

 

[2023]

Hello, I understand there is an area of overlap where stones just based on dimensions alone that appear to meet both AGS0 and GIA ex cuts may not pass HCA, the response I was given on this forum was AGA0 stones have been assessed for light assessment, so whilst people may automatically disregard the GIA stone, it doesn't matter for an AGS0 stone...

As for colour all I know is that GIA has at least two people independently compare the stone to a master set and independently input colour separately, if the colours are not the same they will not grade the stone that colour. GIA also assesses stones in real life lighting conditions...I don't know what AGS does.

Just my 2cts

 

[JulieN]

THat one is ok. Maybe PSers are too strict.

 

[diamondseeker2006]

I think the stone is fine, too. I have been educated a little by Yssie and Jonathan and now understand that a stone can have a spot or two or leakage that is undetectable to the eye and does not affect light performance. The ASET on that stone does not show a ring of leakage. One should expect more perfection when they are paying for "hearts and arrows" cut, though.

I do find the color comments very interesting because I agree from my own experience having had both GIA and AGS stones. And in fact, I have proof, because I bought one stone that was GIA H and was told that it was a high H, and later I had it graded by AGS, and it became a G. Sooo, it causes me a dilemma because I almost have to go up a color grade on AGS stones which can get expensive.

Surely we are close to the day of having technology that can assess color with 99% accuracy.

 

[alene]

I've heard before that AGS was more lenient on color at times but thought it was more exception to the rule rather than a consistent pattern. My AGS H has been appraised as an H several times, though I have been told repeatedly that clarity was graded too strictly and would've been higher had it been graded by the GIA.

 

[Laila619]

I think the stone is fine, too. I have been educated a little by Yssie and Jonathan and now understand that a stone can have a spot or two or leakage that is undetectable to the eye and does not affect light performance. The ASET on that stone does not show a ring of leakage. One should expect more perfection when they are paying for "hearts and arrows" cut, though.

I do find the color comments very interesting because I agree from my own experience having had both GIA and AGS stones. And in fact, I have proof, because I bought one stone that was GIA H and was told that it was a high H, and later I had it graded by AGS, and it became a G. Sooo, it causes me a dilemma because I almost have to go up a color grade on AGS stones which can get expensive.

Surely we are close to the day of having technology that can assess color with 99% accuracy.

That's a computer generated ASET though, not the real deal.

I can see the leakage in the actual pic. The dark ring in the middle will not reflect light like the rest of the stone.

A 35.3 crown with a 41.3 pav should not be getting an ideal cut grade.

 

[2023]

On the crown an pav angle you stated it does look like it sits outside AGS ideal between 2-4 grade, which is potentially not even an excellent AGS. Am only basing that on the two numbers though pav and crown.

Maybe AGS0 diamonds also need a request for idealscope images and to look at dimensions further? There was an AGS0 stone listed before with an IS image that had a white ring of leakage, though seemed to fall in the right Price Scope parameters (HCA) and most posters said it wouldnt be noticeable.

If you post more examples of this maybe a jeweller will chime in or at least other posters if real IS images are posted.

Definitely is interesting.

 

[0-0-0]

IMO, if you are picky about leakage, painting/digging, and/or optical symmetry, it is always a must to get ASET/IS images. A GIA EX / AGS 0 with cherry numbers as noted on the reports and a great HCA score can still have any of the above issues, depending on how precisely the stone is cut.