AGS vs GIA color grades

[Serg]

Paul, you mentioned many retailers prefer GIA - do you know why that is? I have never been able to find a B&M store that carried AGS graded stones, and I've always wondered why!

Several reasons

one of most important reason what GIA has grading Laboratory in Mumbai and for Indian cutters are more faster to receive GIA paper than AGS paper.( and most probably more cheap )

interesting what Before ASG introduced Gold/Platinum reports, AGS service was quite popular in Surat. but then most cutters forgot about AGS( may be because GIA opened window in Mumbai to collect diamonds, may be because ASG lost mystery and GIA EX could give better yield with similar cut quality for most consumers)

 

[diamondseeker2006]

There have been a couple of instances here where PS members bought AGS stones and the independent appraisals came in a color grade lower. And in my personal experience, I have had an H color GIA H&A stone and H color AGS stones, and I could absolutely see more tint in the H color AGS stones especially from the side. I had no problem buying a GIA stone, though, because I bought it from Good Old Gold who runs the extra tests to confirm ideal cut quality. In that respect, I was able to get a strong color and top cut quality. I went up to G in my last pair of AGS studs and find them to be quite white/near colorless.

 

[Paul-Antwerp]

What also happens is that both GIA and AGS have a similar procedure of accepting stones, giving a first grading-result, leaving the option to ask for a re-check (disagree) and then issue a final grade.

I have never met a retailer (sending in stones to GIA) who knew about the GIA-procedure, and thus, they stood a higher chance of getting a stricter than necessary grade from GIA.

This difference in information leads to different results and most probably different perception. In some cases, not giving your customers good service might be good marketing, it seems.

Live long,

 

[kal2021]

Paul, thank you SO much for your thoughtful and thorough response to my question. I really appreciate it - the question I posed has been confusing me for some time now, and I am happy to finally have an answer I can understand and trust! I recently picked out an AGS000 H&A stone from BGD that is an H, VS2. I hope it checks out to be just that once we get it appraised!

 

[Tom Gelb]

What also happens is that both GIA and AGS have a similar procedure of accepting stones, giving a first grading-result, leaving the option to ask for a re-check (disagree) and then issue a final grade.

I have never met a retailer (sending in stones to GIA) who knew about the GIA-procedure, and thus, they stood a higher chance of getting a stricter than necessary grade from GIA.

This difference in information leads to different results and most probably different perception. In some cases, not giving your customers good service might be good marketing, it seems.

Live long,

Hello Paul,

Golly! Are you saying that retailers do not know about re-checking color at the GIA, but do at the AGS lab?

Tom

 

[Paul-Antwerp]

Hi Tom,

I do not know if they do at the AGS-lab either, but they sure do not know about the system at the GIA-lab.

The big difference is this, based upon my experience with both labs:

Sending in 10 stones into GIA, I need to ask for re-check on 8 on average, because I do not agree with colour or clarity. Out of the re-checks, they agree and change more than 80% of the times.

Sending in 10 stones into AGS, I need to ask for re-check on 4 on average, because I do not agree with colour or clarity (most often on clarity). Out of the re-checks, they agree and change less than 25% of the times.

With that experience, not knowing about the re-check-system at GIA makes a huge difference, while the difference is minor at AGS.

Live long,

 

[slg47]

is re-checking grades common?

 

[Paul-Antwerp]

It is a standard-procedure, at least if the lab informs you.

 

[WinkHPD]

I just want to chime in here as a retailer.

I had some stones with PGS papers on them. I sent some of them to AGS for grading reports and on one of them I disagreed with the AGS grade and called up to ask.

They checked the stone and told me that they thought it was a close borderline call but that they came in south of the border.

As it was the line between VS2 and SI1 I took quite a hit on the gem when I sold it with the AGS paper.

I was impressed at a couple of things. One that they would give me the option to ask for a recheck, and two, that they would tell me what they found. I am a tight grader and know that I felt they were too tight on that stone, it was clearly a low VS2 in my book.

I have argued with them twice about SI2 stones that they were calling I1's and both times GIA gave me the grade the diamond deserved. Several years ago AGS took a serious look at their grading of I1 and SI2 and found that they were indeed to strict in accordance with the GIA system that they were using and realigned their grading to be in conformance (as much as possible) with GIA.

I have always been impressed with AGS in their quest to be a top tier lab of excellent repute. They constantly strive to excel at what they are doing and constantly check and recheck their procedures to assure that they are doing their job correctly.

Then of course there is their outstanding research that led to the development of what is undeniably the finest cut grading system currently available in the world. (This will be disputed by some... Which obviously makes my statement about undeniability an oxymoron)

Wink

 

[Yang Kin]

You are right, Yssie, in the sense that a lab is only a reporter, but has no direct influence on the quality of a diamond.

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.

Live long,

Hi Paul,

I know this is an old thread, but then I would like to whether your experience with AGS below still stands true:

- 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.

Hi Tom,

I do not know if they do at the AGS-lab either, but they sure do not know about the system at the GIA-lab.

The big difference is this, based upon my experience with both labs:

Sending in 10 stones into GIA, I need to ask for re-check on 8 on average, because I do not agree with colour or clarity. Out of the re-checks, they agree and change more than 80% of the times.

Sending in 10 stones into AGS, I need to ask for re-check on 4 on average, because I do not agree with colour or clarity (most often on clarity). Out of the re-checks, they agree and change less than 25% of the times.

With that experience, not knowing about the re-check-system at GIA makes a huge difference, while the difference is minor at AGS.

Live long,

Also, I think this is going to be stupid question, but then I am still curious - When you disagree with the result of a grading, will it be because the result came back to be better than what you have expected?

Many thanks!

 

[Paul-Antwerp]

Hi Yang,

Thank you for your questions in this old thread.

Lately, something like the last year, I should say that GIA has grown more lenient in Color. On top of that, I also see extreme leniency in GIA with regards to grading fluorescence. The 'trade' at large blames it to the GIA-Mumbai-lab specifically being more lenient, but I have the experience with GIA-Karlsbad.

As for re-checking, we personally re-check also for downgrades, in other words if we think the grade given is too lenient. Labs however indicate that we are exceptions in asking for downgrades.

Live long,

 

[Yang Kin]

Hi Yang,

Thank you for your questions in this old thread.

Lately, something like the last year, I should say that GIA has grown more lenient in Color. On top of that, I also see extreme leniency in GIA with regards to grading fluorescence. The 'trade' at large blames it to the GIA-Mumbai-lab specifically being more lenient, but I have the experience with GIA-Karlsbad.

As for re-checking, we personally re-check also for downgrades, in other words if we think the grade given is too lenient. Labs however indicate that we are exceptions in asking for downgrades.

Live long,

Thanks @Paul-Antwerp!

Since GIA has grown more lenient in colour, will this make it on par with AGS, or even worse, at this point of time?

You mentioned that certain GIA labs are more lenient, but how about the other GIA labs? Is there anyway we can find out which lab graded a particular GIA diamond?

This makes me think of another question - How about AGS? How many labs are there obvious differences between one lab and the other?

Thank you!

 

[Paul-Antwerp]

Thanks @Paul-Antwerp!

Since GIA has grown more lenient in colour, will this make it on par with AGS, or even worse, at this point of time?

You mentioned that certain GIA labs are more lenient, but how about the other GIA labs? Is there anyway we can find out which lab graded a particular GIA diamond?

This makes me think of another question - How about AGS? How many labs are there obvious differences between one lab and the other?

Thank you!

Hi Yang Kin,

I would today say that GIA grade on-par (roughly) in Color.

AGS has only one lab-location. It may be why there is more consistency in their grading. Running various lab-locations (like GIA) is a challenge with regards to consistency. Personally, when considering a purchase of GIA-graded diamonds, I always want to check them out in-hand, in my office.

I did not say that a specific GIA-location is more lenient. As one cannot know where it was graded, unless you send it the diamonds yourself, blaming apparent inconsistency and/or leniency on one lab is an incorrect practice, often heard within the trade.

Live long,

 

[Yang Kin]

Hi Yang Kin,

I would today say that GIA grade on-par (roughly) in Color.

AGS has only one lab-location. It may be why there is more consistency in their grading. Running various lab-locations (like GIA) is a challenge with regards to consistency. Personally, when considering a purchase of GIA-graded diamonds, I always want to check them out in-hand, in my office.

I did not say that a specific GIA-location is more lenient. As one cannot know where it was graded, unless you send it the diamonds yourself, blaming apparent inconsistency and/or leniency on one lab is an incorrect practice, often heard within the trade.

Live long,

Hi @Paul-Antwerp,

Thanks for the clarification and thank you for correcting the my statement. Apologies for that.

 

[Sparkly2017]

Hi Yang,

Thank you for your questions in this old thread.

Lately, something like the last year, I should say that GIA has grown more lenient in Color. On top of that, I also see extreme leniency in GIA with regards to grading fluorescence. The 'trade' at large blames it to the GIA-Mumbai-lab specifically being more lenient, but I have the experience with GIA-Karlsbad.

As for re-checking, we personally re-check also for downgrades, in other words if we think the grade given is too lenient. Labs however indicate that we are exceptions in asking for downgrades.

Live long,

Very interesting topic. Thank you @Yang Kin for reopening this and @Paul-Antwerp for the response. I heard from a reputable jeweller that GIA in India (not sure which) grading was very relaxed and there's a potential scandal there....