AGSL vs GIA in color & clarity?

[c-k]

I have read several threads/posts in which someone has stated that AGSL grades softer than GIA in color & clarity.

Is this true? and how does one know this?

 

[SB621]

The search tool or google will point out many threads about this on PS I think the one below that I linked to will answer most of your questions.


https://www.pricescope.com/wiki/diamond-grading

And I think you mean EGL grades softer then GIA.

 

[c-k]

The search tool or google will point out many threads about this on PS I think the one below that I linked to will answer most of your questions.


https://www.pricescope.com/wiki/diamond-grading

And I think you mean EGL grades softer then GIA.

No, not EGL.....AGSL vs GIA That thread you have is 9 years old, I am speaking with standards of today in which there have been comments on this.

 

[hearts-arrows_girl]

I haven't seen any studies or articles that prove this, but I have seen a few posters casually mention that AGS could be softer on color grading than GIA. So I am not sure if it is fact or myth. I too am curious. I hope someone more qualified can give us an answer.

 

[diamondseeker2006]

Yes, we have seen many circumstances of AGS stones being appraised as a grade lower in color or graded by both labs and GIA would grade a grade lower. But, I truly believe this mainly happens with borderline stones. I had a GIA H&A diamond that the vendor told me was a high GIA H when I bought it. When I traded it in, it was regraded as AGS G. I have seen other examples of this on here. But no one knows the percentage of stones affected. I continue to buy AGS graded stones and avoid ones that I think are at the low end of their color grade.

 

[TC1987]

I've read on here that AGS grades a bit softer on color but I haven't heard that about clarity. AGS gets the best-cut stones, though, because their top cut grade is more discriminating and less broad than GIA's or EGL's.

If the vendor has a colorimeter machine, that can be used check the color and whether the stone is high or low in that grade. Or you can have an independent appraiser examine it. Or, D white color is what most colorless CZs are, if you are looking at D/E range. I can see tint from the side in an F. Seeing color (or color differences) is something that you can train yourself to do. I color band, as defined by GIA, is the narrowest band of near-colorless, or so I have read hear on PS. J and lower start to be wider. D, E, F are pretty narrow, too.

 

[kenny]

I'm suspicious that there is a process going on in which PS discussions solidifies things facts that are not facts.

I'll consider AGS and GIA equal till I see double blind scientific proof of a large set of data the proves otherwise.
Onezies Twozies and hearsay and repetition of, "what I heard" or "what I read" are not enough for me.

What happens on PS can be powerful, persuasive and frankly creepy at times.

I perceive AGS and much more pro-consumer and GIA as much more pro-industry.
GIA's huge loosie-goosie and industry-friendly "Excellent" cut grade includes those less-attractive, but more-profitable and weight-saving steep deeps.

When choosing between two diamonds, all other things being equal I'd support AGS by buying a stone graded by AGS over one graded by GIA.

 

[CharmyPoo]

I think the study sarabear linked is great and would love love to see a refresh.

My opinion is that AGS is softer in color than GIA (no personal proof other than stories from PS). EGL-USA and Canada is 1 grade softer in colour and on par on clarity (my personal experience on a sample size of 3).

 

[SB621]

The search tool or google will point out many threads about this on PS I think the one below that I linked to will answer most of your questions.


https://www.pricescope.com/wiki/diamond-grading

And I think you mean EGL grades softer then GIA.

No, not EGL.....AGSL vs GIA That thread you have is 9 years old, I am speaking with standards of today in which there have been comments on this.

Well regardless of when the study is published it has very good information if you took the time to read it. Like Charmy said I would love to see what Wink would find if he updated it (hint hint it you are reading this ).

 

[diamondseeker2006]

I can think of a few people that had this experience besides me. I think Dreamer sold a stone that was graded a grade higher when sent to AGS, pretty sure Butterfly did, Harriet had 2 independent appraisers say that her I color AGS stone was actually J, and there have been others. Like I said, 95+% (just a number out of my head) of the grades might be the same within a color grade. It is likely the borderline ones that AGS bumps up. I would not be afraid to buy AGS stones. But I also often buy them from someone who checks them with a colorimeter for me.

 

[denverappraiser]

But I also often buy them from someone who checks them with a colorimeter for me.

You find colorimeters to be a reliable way to evaluate color?

 

[GreenBling]

But I also often buy them from someone who checks them with a colorimeter for me.

You find colorimeters to be a reliable way to evaluate color?

My apologies for side tracking... how would fluor affect accuracy of the colorimeter? And do AGS and GIA use it?

 

[diamondloveaffair]

fluorescence won't affect the color measured by the colorimeter

 

[diamondloveaffair]

at least not in the majority of the times.

 

[c-k]

I can think of a few people that had this experience besides me. I think Dreamer sold a stone that was graded a grade higher when sent to AGS, pretty sure Butterfly did, Harriet had 2 independent appraisers say that her I color AGS stone was actually J, and there have been others. Like I said, 95+% (just a number out of my head) of the grades might be the same within a color grade. It is likely the borderline ones that AGS bumps up. I would not be afraid to buy AGS stones. But I also often buy them from someone who checks them with a colorimeter for me.

Just my opinion, but with such a very small sampling that you have given would not be enough to really compare.

I know clarity can be very subjective, but I would think less so with color grading, as I understand both GIA & AGSL use the same master sets for color grading. I would assume that they use the same lighting conditions as well, I don't know.

Yes, both labs do state that one grade up or down is possible even with all their standards/procedures in place. But I really can't find anywhere that one lab is more or less restrictive or softer than the other. Given that both labs give their 'opinion' using qualified personnel, using industry standards, and both are very well respected.

Again, just my thoughts as I am trying to learn and understand how important to purchasing a diamond is with regards to lab grading reports from GIA and AGSL. I know that the reports are an opinion, but there is a value to that report. I just purchased a pair of diamond studs (GIA - G color VS tripleXXX) and I LOVE them. The color looks very white to me, and reading on this site for a year, I decided on G color, the lab report was important to me and I know I paid more to get diamonds that were graded with a report from a respected grading lab, I think would have purchased either GIA or AGSL.

 

[diagem]

I think it's a fluid question...
Too many factors involved with human subjectivity.

For example...

I feel there is more consistency in the color grading of the lower colors (e.g. JKLMN) at AGSL vs. GIA.
Hence the fact that GIA issues double grades on the low colors when reaching O-P, Q-R, S-T, U-V, W-X, Y-Z.
I believe AGSL offers single grades at these color grade ranges. (I have not witnessed all but do recall getting O-P-Q and R's as single calls)
Maybe someone else witnessed double grades at AGSL, it would be interesting to hear.

I personaly resubmitted quite a few Diamonds for GIA regrading after disagreeing with the grade calls and getting the grades I anticipated the second time around. With AGSL it was way more difficult getting them to change the grades to my anticipations.

Earning a "D" color at AGSL is quite harder than earning one at GIA..., that is a fact I can definitely vouch for.
Clarity wise, I am convinced AGSL is quite a bit harsher than GIA almost across the board. In my experience GIA will set a VS2 clarity call on a center black crystal inclusion much easier than AGSL any day! Same with some with transparent feathers..., AGSL would call them SI's while GIA will call them VS's.

I just completed a 2.55ct Old-Mine Brilliant which has a medium to smallish group of center colorless inclusions which I am confident would earn a VS1-2 at GIA, I wouldn't be surprised if AGSL calls it an SI1, if they do I plan on disputing the grade vigorously. But it gives you an example of how I feel the difference is between the two Labs at subject.

Regarding colorimeters..., I don't believe they are reliable enough to seriously call any color grade. (period). But that is only my opinion.

 

[Christina...]

I'm suspicious that there is a process going on in which PS discussions solidifies things facts that are not facts.

I'll consider AGS and GIA equal till I see double blind scientific proof of a large set of data the proves otherwise.
Onezies Twozies and hearsay and repetition of, "what I heard" or "what I read" are not enough for me.

What happens on PS can be powerful, persuasive and frankly creepy at times.

I perceive AGS and much more pro-consumer and GIA as much more pro-industry.
GIA's huge loosie-goosie and industry-friendly "Excellent" cut grade includes those less-attractive, but more-profitable and weight-saving steep deeps.

When choosing between two diamonds, all other things being equal I'd support AGS by buying a stone graded by AGS over one graded by GIA.

Kenny I 110% agree with you and am pleased that you posted this observation. It's often difficult to separate a posters thoughts, theories, and opinion from actual fact when the thought, theory, or opinion isn't stated as such. Like you, I've noticed that oft repeated opinion can quickly become fact here without any supporting documentation.

 

[John P]

We submit hundreds of diamonds to both labs. Furthermore, we spend weeks romancing each stone, whereas the lab graders have just a "dinner-date" with them. Consequently, I think we're in a strong position to grade the graders.

I find the agreement between AGSL and GIA's locations when it comes to color, clarity and finish to be eerily strong. If someone wants to say that AGSL's color masters have soft borders in some cases then it must be acknowledged that GIA's clarity thresholds are equally soft in other cases. Let us remember that every lab sets their own benchmarks, which is completely fair. And since the commonly accepted tolerance (per appraisers) when grading un-mounted diamonds is one grade either way I find AGSL and GIA results extremely in-sync...far more in-sync than that that acknowledged tolerance allows.

Since no one else has mentioned it, I feel I should mention that AGSL has only one location with a small team of gemologists. They are consistent with themselves... Meanwhile GIA has many worldwide locations with hundreds of grades issuing tens of thousands of reports per week. Logically (even unavoidably) there are inconsistencies between those locations. In fact, it's not unheard-of for a trader who didn't get the desired grade at one GIA lab to polish off the inscription(s) and send the diamond(s) to a more "friendly" location, hoping for a better outcome.

 

[c-k]

Re: AGSL vs GIA in color & clari

Thanks to everyone who shared their expertise....great information, great insight. I believe my question was answered.

 

[Charlize]

Very interesting and insightful thread!

 

[CharmyPoo]

I really wish some of our awesome trade members here will repeat the study done before. I understand the sample size is small but still very telling. To me, the study represents facts for those diamonds studied. I have any my diamonds I multiple labs just to serve my own curiosity slough I have not tried ags.

 

[diamondseeker2006]

All I can say is the one colorimeter that has been used for stones I have been interested in has been on target 100%. It predicted the GIA H stone was borderline G, the stone was sent to AGS and graded G. It has been used to differentiate high and low color I with accuracy proven by the eyes. One colorimeter may not be well calibrated with another, but using one can help judge between multiple stones.

I have also heard the thing about AGS being stricter on clarity, but I have found my GIA VS1's to be extremely clean and the one regraded by AGS remained VS1. Maybe there is more discrepancy down in the VS2-SI2 range perhaps. And I would be super careful about that if I were looking at SI stones. We haven't heard too many stories here about discrepancies in clarity grading like we have about color, though.

I just say this because most people do not have diamonds regraded by another lab and most do not have an independent appraisal. But it has happened here so many times, that I am very careful not to buy an AGS stone that I think is on the low end of a color grade because I'd potentially be paying for a color grade higher than it really is. Never once have I seen a stone go for regrading here and get a lower color grade by AGS than the GIA grade, but the opposite has happened enough times to be notable. And we are talking about many thousands of dollars in value when a J is bumped to I, an H is bumped to G, and especially when (I think it was butterfly's) G diamond was regraded as F when it was traded in. I was lucky, I resold my stone and made several thousand dollars because of the regrading. So it can be advantageous if you are aware. Not a scientific study, no. But facts based on many experiences reported here.