GIA vs AGS

[shoppingqueen]

GIA is very reputable in the world of grading diamond. I would like to find out more about AGS too. How does it compare to GIA as to upholding the grade standard? Thank you.

 

[stone-cold11]

AGS is on par with GIA on color and clarity grading, stricter criteria for cut grading.

 

[shoppingqueen]

GIA certificate is more prevalent than AGS? Is there a reason? Thank you.

 

[stone-cold11]

GIA is a bigger lab, also their Ex cut grade are more easy to achieve than a AGS0 ideal cut grade, which is an advantage to the cutters, so they get more customers.

 

[Regular Guy]

Ditto Stone (on 2 of his 3 points...that it's a bigger lab is though a tautology)...

Date: 9/22/2009 12:55:30 PM
Author: shoppingqueen
GIA certificate is more prevalent than AGS? Is there a reason? Thank you.

Someone knowing historical developments can review better. The background in the tutorial should be helpful.

Understanding that a less precisely made cut, and also, one done where weight is less sacrificed for performance, can help explain, too, since top grades are more easily earned for GIA than for AGS, where the target is harder to hit, regardless of which of the two reports are sought after for AGS...when the intent is to secure the top grade in cut from which ever grading agency is engaged.

 

[kenny]

GIA's top cut grade allows cutters to make more money.
GIA allows diamonds that are too deep to look their best to still get GIA's top cut grade.
This means the cutters grind away less rough diamond material and end up with a heavier stone than if they were to cut the diamond to get AGS's more-strict top grade.

Personally I think of AGS as looking out for the public and GIA as looking out for the industry.
This is why, when possible and all other things being equal, I will select an AGS stone over a GIA stone.

 

[WinkHPD]

Date: 9/22/2009 12:55:30 PM
Author: shoppingqueen
GIA certificate is more prevalent than AGS? Is there a reason? Thank you.

Partially for some of the reasons given after this post by Stone Cold, Regular Guy and Kenny but also for the principle of preeminence. GIA did it first, thus is better known and better accepted, especially by those who are simply looking for a nice diamond and heard that they are the trade standard.

To actually be looking for an AGS graded diamond you must learn first enough about diamonds to appreciate cutting and the minute points that make a visual difference so that you can understand that when it comes to cutting AGS might well be the better choice of labs.

Then you have to have cutters who are willing to make these potential clients their target market rather than just cutting "good enough" to get a GIA EX grade. Unlike AGS, to get the top GIA EX cut grade you can have less than top Polish and Symmetry. AGS requires an Ideal in its three areas (Light Performance, Polish and Symmetry) to designate a diamond as an Ideal cut diamond.

Wink

 

[shoppingqueen]

Does AGS have a cut grade harder to achieve at every level or it only holds true for the AGS0 ideal cut level? Thank you for this valuable information.

 

[denverappraiser]

Mostly people get into AGS graded diamonds because they like the AGS approach to cut grading and they want to demonstrate a superior cut to their clients. That makes for a peculiar market reality for the AGS 0-10 cut grading scale.

0 means ideal cut. Yippie.
1 means the dealer thought it was an ideal cut but missed for one reason or another. Bummer.
2 means the dealer who submitted the job didn’t understand the question. They won't make that mistake again.
3 – 10 means the dealer was stupid and for some reason no one has sent it somewhere else to be redone. They should have sent it to a different lab in the first place. A stone 'certified' by AGSL as a bad cut would be one of the hardest things to sell in the whole diamond industry.

Nearly every AGS graded stone in the marketplace is going to be ideal and those that miss are 1's. The others get sent elsewhere for grading. You see no GIA-poor or GIA-fair and darned few GIA-good gradings for the same reason. Those stones get their pedigree somewhere else.

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Appraisals in Denver

 

[Todd Gray]

Date: 9/22/2009 1:27:57 PM
Author: shoppingqueen
Does AGS have a cut grade harder to achieve at every level or it only holds true for the AGS0 ideal cut level? Thank you for this valuable information.

The Light Performance factor of the overall cut grade standard by the AGS makes it more difficult to obtain a rating of AGS Ideal 0 for overall cut than GIA Excellent which does not include a rating for visual performance.

 

[Todd Gray]

Date: 9/22/2009 1:39:11 PM
Author: Todd Gray

Date: 9/22/2009 1:27:57 PM

Author: shoppingqueen

Does AGS have a cut grade harder to achieve at every level or it only holds true for the AGS0 ideal cut level? Thank you for this valuable information.

The Light Performance factor of the overall cut grade standard by the AGS makes it more difficult to obtain a rating of AGS Ideal 0 for overall cut than GIA Excellent which does not include a rating for visual performance.

After posting, I realized that it should be noted that the playing field can be leveled a bit by use of an ASET scope to evaluate GIA graded diamonds... Other scopes such as the Ideal Scope and Gems Fantasy Scope provide additional insight. And of course, you should refer to a facet-by-facet breakdown of the diamond structure by way of a Sarin / OGI / Helium / computerized proportions analysis regardless of whether the diamond is graded by the GIA or AGS (or anybody else) to better define the basis of the proportions grade - refer to the Sarin 3D or Manufacturers report for this information and look at the spread between the high and low measurements for each section and how they stairstep (flow) from one facet to the other.

 

[Lorelei]

Date: 9/22/2009 12:40:23 PM
Author:shoppingqueen
GIA is very reputable in the world of grading diamond. I would like to find out more about AGS too. How does it compare to GIA as to upholding the grade standard? Thank you.

www.agslabs.com

Also AGS's cut grading is considered to be preferable by some to GIA as AGS cut grade for AGS0 is performance based, GIA proportion based. I will also link a few threads for you concerning GIA's cut grading.

Also this page gives a basic overview on how the grading labs rank.

https://www.pricescope.com/community/threads/2006-gia-grading-report-post-info-here-please.38131/

https://www.pricescope.com/community/threads/gia-ex-let-the-buyer-beware.41371/

https://www.pricescope.com/community/threads/consumer-advisory-gia-cut-grade-rounding-problems.39401/

 

[haagen_dazs]

Date: 9/22/2009 1:39:08 PM
Author: denverappraiser

Those stones get their pedigree somewhere else.

Like HRD? EGL? and some other unknown labs?

 

[haagen_dazs]

Also AGS's cut grading is considered to be preferable by some to GIA as AGS cut grade for AGS0 is performance based, GIA proportion based. I will also link a few threads for you concerning GIA's cut grading.


Also this page gives a basic overview on how the grading labs rank.

from the link
"Drop outs end up in a ‘program’ at a chain store or Joe's Bar & Grading Lab."

ahhhh
haha so sad =(

 

[stone-cold11]

HRD, unlikely, they are quite strict also apparently, just not common in US, more in Europe.

EGL probably, or other smaller labs, even in-house grading?

 

[Lorelei]

Date: 9/22/2009 2:59:20 PM
Author: haagen_dazs

Date: 9/22/2009 1:39:08 PM
Author: denverappraiser

Those stones get their pedigree somewhere else.

Like HRD? EGL? and some other unknown labs?

HRD are actually a well regarded lab, better known in Europe than the US.

 

[Black Jade]

I understnad that EGL USA is respectable, but EGL Israel for instance, is not.

AGS 000 will be a perfect stone. You can be sure of that. You will also pray a premium for this--they cost a bit more.
There are other stones that are as pretty, in person, but you can buy AGS 0 sight unseen and be sure what you will get.

AGS does not grade all kinds of stones, however. They grade round brillia nts and princess cuts. They do not grade fancy shapes or fancy colors. You need GIA for that.

I hope someone will correct anything incorrect that I have said.

 

[haagen_dazs]

Date: 9/22/2009 5:21:40 PM
Author: Black Jade

AGS does not grade all kinds of stones, however. They grade round brillia nts and princess cuts. They do not grade fancy shapes or fancy colors. You need GIA for that.

interesting... i did not know that..

 

[denverappraiser]

Date: 9/22/2009 2:59:20 PM
Author: haagen_dazs

Date: 9/22/2009 1:39:08 PM

Author: denverappraiser

Those stones get their pedigree somewhere else.

Like HRD? EGL? and some other unknown labs?

A stone that would get AGS/G/VS2/3 but would get GIA/G/VS2/ex would go to GIA for obvious reasons.

A stone that would get AGS/G/VS2/7 but might get an E/VS1 I with no mention of cutting at all may go to the less regarded lab even though there’s going to be a discount applied at sales time. It’s a discount from E/VS1 after all. If 90% of the shoppers avoid it because they don’t like the lab, that means that 10% might buy and, besides, no one will buy an AGS-7 anyway.
.
There’s also IGI, HRD, regional labs in different countries, labs that specialize in ebay vendors, etc.

There are dozens or even hundreds of players in the lab grading business.

That same stone may be sold without paperwork at all.

It’s not unusual for a dealer to send it to several labs and choose the paperwork based on which one seems most favorable at the time. It’s not even unheard of to simultaneously market a stone with an offer of different paperwork into different markets.

Labs are chosen strategically and it’s a big deal. A single grade can mean thousands of dollars or can be the difference between a stone that gets sold before it’s even back from the lab and one that sits in inventory for years. The decision may be because they want to be graded on a different clarity scale or judged using different standards. They may want to have a particular cut scale applied or they may want to avoid using a particular cut grading system. Most people who are submitting stones to the labs are experienced manufacturers and dealers and the primary purpose is to get an advertisement that they can then use to sell the stone. By and large they’re an informed bunch who are well aware of the tradeoffs and who are making this decision in their own enlightened best interest, interests that are not necessarily shared by the final consumer.

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Appraisals in Denver

 

[denverappraiser]

Date: 9/22/2009 5:21:40 PM
Author: Black Jade

AGS does not grade all kinds of stones, however. They grade round brillia nts and princess cuts. They do not grade fancy shapes or fancy colors. You need GIA for that.


I hope someone will correct anything incorrect that I have said.

This isn’t correct. They only have a cut grading system for modern round brilliant, princess, oval and emerald cuts (the latter 2 services being sufficiently unpopular that they aren’t really relevant in the marketplace) but they’ll grade pretty much anything someone is willing to pay them to grade. They just don’t assign a cut grade on anything other than those 4.

Neil Beaty
GG(GIA) ICGA(AGS) NAJA
Professional Appraisals in Denver

 

[stone-cold11]

Date: 9/22/2009 5:21:40 PM
Author: Black Jade
AGS does not grade all kinds of stones, however. They grade round brilliants and princess cuts. They do not grade fancy shapes or fancy colors. You need GIA for that.

They grade cuts for emerald and oval too.

http://agslab.com/faqs_cut_grade_information.php#faq18

 

[diamondseeker2006]

Just understand that there are plenty of stones within the GIA Excellent category that would be equivalent to an AGS Ideal cut. It does not mean that AGS Ideal cut is superior to all GIA Excellent stones. Jonathan at GOG is one who tests the stones to handpick GIA Excellents that have AGS0 light performance.

 

[elle_chris]

Date: 9/22/2009 6:12:58 PM
Author: diamondseeker2006
Just understand that there are plenty of stones within the GIA Excellent category that would be equivalent to an AGS Ideal cut. It does not mean that AGS Ideal cut is superior to all GIA Excellent stones. Jonathan at GOG is one who tests the stones to handpick GIA Excellents that have AGS0 light performance.

Very true.

Before John started using AGS, he was using GIA and selling the same beautiful H&A stones. In fact, my pendant is a GOG H&A with a GIA report that''s just stunning.

 

[Regular Guy]

Oy Vey

Date: 9/22/2009 1:39:11 PM
Author: Todd Gray

Date: 9/22/2009 1:27:57 PM
Author: shoppingqueen
Does AGS have a cut grade harder to achieve at every level or it only holds true for the AGS0 ideal cut level? Thank you for this valuable information.

The Light Performance factor of the overall cut grade standard by the AGS makes it more difficult to obtain a rating of AGS Ideal 0 for overall cut than GIA Excellent which does not include a rating for visual performance.

Todd &Lorelei...I think we should just be clear...and understand that when you go to some Burger Whop store, and ask for medium and they tell you, sorry, we only have large, enormous, and colossal...you can still get what you want (probably).

AGS has come out with what they call "performance" based...but they are just nailing it better than they used to...though even that language isn''t current...since the performance now equated to their current platinum. But...when they present gold, and there, they present "proportion" based...they are still also presenting performance...too! They''re just not locking on with the same precision.

Proportions presentation, in the form of a valuation and grade...which GIA did in 2006 or so (as your threads document, Loreiei), is a representation about performance. It''s not the same as AGS, and is not so narrowly defined for best. But we shouldn''t buy into AGS''s marketing, and say that if it''s not platinum, you don''t know what you''re getting.

Procedurally, Todd, you come back to this with your mention of reflector tools. But, as soon as cut grades are assigned at all...the intent is to rank performance, absolutely.

 

[Lorelei]

Date: 9/22/2009 7:14:05 PM
Author: Regular Guy
Oy Vey

Date: 9/22/2009 1:39:11 PM
Author: Todd Gray

Date: 9/22/2009 1:27:57 PM
Author: shoppingqueen
Does AGS have a cut grade harder to achieve at every level or it only holds true for the AGS0 ideal cut level? Thank you for this valuable information.

The Light Performance factor of the overall cut grade standard by the AGS makes it more difficult to obtain a rating of AGS Ideal 0 for overall cut than GIA Excellent which does not include a rating for visual performance.

Todd &Lorelei...I think we should just be clear...and understand that when you go to some Burger Whop store, and ask for medium and they tell you, sorry, we only have large, enormous, and colossal...you can still get what you want (probably).

AGS has come out with what they call 'performance' based...but they are just nailing it better than they used to...though even that language isn't current...since the performance now equated to their current platinum. But...when they present gold, and there, they present 'proportion' based...they are still also presenting performance...too! They're just not locking on with the same precision.

Proportions presentation, in the form of a valuation and grade...which GIA did in 2006 or so (as your threads document, Loreiei), is a representation about performance. It's not the same as AGS, and is not so narrowly defined for best. But we shouldn't buy into AGS's marketing, and say that if it's not platinum, you don't know what you're getting.

Procedurally, Todd, you come back to this with your mention of reflector tools. But, as soon as cut grades are assigned at all...the intent is to rank performance, absolutely.

I probably wasn't clear, I said AGS0 was performance based, not referring to AGS other cut grades. Absolutely some proportion based cut graded diamonds can be stunners to include GIA, I was referring to the above in a very broad sense that generally AGS cut grading is considered preferable to GIA especially keeping in mind the forced rounding subject with GIA. I also try to champion all kinds of diamonds, not that AGS0 is the only way to go and have done for some time now.

And I don't like burgers, couldn't you have used cakes or chocolate for your comparison Ira?

 

[Judah Gutwein]

A very interesting question and a popular topic, not only amongst consumers but within the diamond industry as well.

I recently met with several customers (on separate occasions) who specifically came to look at 2 identical diamonds (same shape, size, color, clarity and spread) with individual AGS000 and GIA EX/EX/EX grading reports (they were interested in comparing identical diamonds with different grading reports) and have subsequently picked any one of the two diamonds as the 'more dispersive' stone to their eyes.

Thus, to lend additional perspective to this thread, I would simply add the following:

It is undisputed, that both the GIA and the AGS command the greatest respect for the stringency of their definitions and grading criteria.
These two labs are considered to be the 'standard bearers' of the industry.

For example:

Unlike with some of the 'mom & pop' labs of rather dubious distinction.., a customer need not worry as much when purchasing a GIA/AGS graded diamond, that the actual color/clarity grades (subjective, by definition on the part of the grader) may very well be lower than what they paid for.

Now when it comes to issuing a cut grade for the most well cut diamonds in the world, could it be that one of these top two labs might be a bit more strict with respect to their individual tolerances and methodologies?

Perhaps.

This question is certainly quite common when comparing these two labs.

However, it is undisputed that there is indeed a "method to the madness" and that the actual science of determining beauty and cut precision which would yield a diamond graded with the coveted GIA EX/EX/EX or AGS000, is going to be a gorgeous diamond of the highest caliber.

Therefore, when you consider which of these two graded stones is going to be a better "light performer", or a (visually) more pleasing diamond to the customer, there is no definite winner and indeed consumer feedback (subsequent to their physical inspection of two such diamonds) is varied.

This salient point, is (imo) a most important consideration.

 

[haagen_dazs]

Date: 9/22/2009 1:39:11 PM
Author: Todd Gray

Date: 9/22/2009 1:27:57 PM

Author: shoppingqueen

Does AGS have a cut grade harder to achieve at every level or it only holds true for the AGS0 ideal cut level? Thank you for this valuable information.

The Light Performance factor of the overall cut grade standard by the AGS makes it more difficult to obtain a rating of AGS Ideal 0 for overall cut than GIA Excellent which does not include a rating for visual performance.

To the experts,
do you think GIA will someday include "Light Performance factor" in their grading reports?
is it a matter of time they establish a criteria or do they not really want to consider the "Light Performance factor" as another gradable factor ?

 

[Regular Guy]

Haagen Daas,

Though not an expert...my argument under the heading "Oy Vey" was apparently not too compelling.

BTW, you might also ask why AGS thinks they can get away providing "performance" based evaluations...without anyone ever being asked how they perform? AGS did no clinical trials, with actual people looking and saying if they liked what they saw. GIA actually asked...a lot of people. Like Tolkowsky did.

 

[HVVS]

Date: 9/22/2009 1:39:08 PM
Author: denverappraiser

0 means ideal cut. Yippie.
1 means the dealer thought it was an ideal cut but missed for one reason or another. Bummer.
2 means the dealer who submitted the job didn't understand the question. They won't make that mistake again.
3 - 10 means the dealer was stupid and for some reason no one has sent it somewhere else to be redone. They should have sent it to a different lab in the first place. A stone 'certified' by AGSL as a bad cut would be one of the hardest things to sell in the whole diamond industry...

Neil Beaty
GG(GIA) ICGA(AGS) NAJA

Professional Appraisals in Denver

Too funny!

Inclusions: In my limited experience, the AGS graded stones have also tended to be significantly cleaner with few and small inclusions, and feathers, if present, were small and not near the girdle or spanning the diameter of the stone. There are some really gunked up GIA SI1 and SI2s out there that look loads worse than the no-name I1 diamond that I own. I've also seen some huge feathers in GIA stones that got top grade for performance but the feathers would be a dealbreaker for me. Local pawn shops are starting to get EGL reports on stones, but those reports show crown and pavilion as %s not angles, and an inclusion the size of a Peterbilt ought to be I1 or I2 but isn't, lol. EGL graded stones often are ones with tables 59% and up.

 

[oldminer]

AGS has limited their lab''s appeal and volume of work by virtue of having built the better quailty report which gives currently consumers the best knowledge of the limited diamond shapes which they do grade. Their success has given them a business dilemma to deal with, namely, How to grow market share without bastardizing their reputation or service product. It is not a easy question to solve.

I am not certain, but it would be my belief that all AGS000 round diamonds fit inside the GIA''s larger "Excellent" rating system. Would those who know for certain please comment? I''d appreciate the advice. Are any AGS000 rounds potentially outside GIA EX?

On the other hand, GIA is far larger and far more well known around the world as a legitimate diamond grading lab. While not so well accepted on Pricescope in the USA, IGI is the pre-eminent diamond lab in India. The world is a large place and there are many players.