Is my GIA XXX also AGS 0, how to tell?

[Jumpin_Jacks]

Picked a great diamond the future fiance bought at a great local brick and mortar. I know GIA XXX doesn't equal AGS 0 in many cases, but how do I tell if I have an AGS 0 as well. I looked at the AGS cut tables (http://www.agslab.com/docs/pbcg/AGSLProportionCharts.pdf) which listed it as Ideal, is that it then or does it need further analysis to confirm? Links to photos of stone here: [URL='https://www.pricescope.com/community/threads/waiting-for-my-custom-set-how-did-i-do-on-stone-price.189700/']https://www.pricescope.com/community/threads/waiting-for-my-custom-set-how-did-i-do-on-stone-price.189700/..[/URL]. BTW, I've seen and worn the ring around the house, goorgeous.

I guess answers here would help anyone looking for those GIA XXX that could be AGS ideal as well. Approx what % do you all gander of GIA XXX also fall into AGS ideal? Thanks in advance, PriceScope is a wonderful wealth of info

GIA 2146107353
HCA: 1.4

ROUND BRILLIANT
Measurements 5.84 - 5.87 x 3.65 mm
Carat Weight 0.77 carat
Color Grade F
Clarity Grade VS2
Cut Grade Excellent

PROPORTIONS
Depth 62.4 %
Table 56 %
Crown Angle 34.5°
Crown Height 15.0%
Pavilion Angle 40.8°
Pavilion Depth 43.0%
Star Length 50%
Lower Half 80%
Girdle Slightly Thick, Faceted, 4.0%
Culet None

FINISH
Polish Excellent
Symmetry Excellent

FLUORESCENCE
Fluorescence None

CLARITY CHARACTERISTICS
Clarity Characteristics Cloud

 

[teobdl]

It's likely that it does, but unless you get more precise measurements, it's impossible to really know because GIA rounds many of the numbers to 5% increments, whereas AGS measures them with more precision.

Here is AGS's cut grading system: http://www.agslab.com/proportion-based-cut-grade.php

For example, the star length is rounded quite a bit in the GIA system. Given a table size of 56%, AGS has a bunch of star length, upper half facet length, and crown angles that are allowable, which in combination with lower facets, give an AGS 0. The star length is rounded to 5%, so maybe it's 47%, maybe it's 52%... now what combination of all the other factors give AGS 0?

It's impossible to know if your diamond really does fall into AGS 0 because rounding on the GIA report doesn't allow you to actually know what a few of those important values really are.

My immediate feeling is that it probably does fall into AGS 0 as far as proportions because a cutter wouldn't just randomly cut those really nice crown and pavilion angle ratios without also probably intending to cut everything else within a nice set of proportions.

Another issue here is that even diamonds with great proportions and symmetry can have facets that are slightly tipped, so internal reflections (and resulting virtual facets) are slightly off. You probably can't appreciate this difference immediately, but there is a difference. Hearts and arrows diamonds w/in the AGS 0 range have to minimize this tipping (called "yaw")... the result is the hearts image that you see in the hearts image.

 

[Just_Starting]

HCA tool > EX EX EX VG 1.4. Also on the chart you can see it fits into the AGS 0 candidate zone, so although from that you can't be sure, it has a good chance to be considering the other aspects of the diamond.

 

[MissGotRocks]

Yes, from first glance it possibly does but on the other hand, if it could obtain that cert, it probably would have been sent. AGS0 stones generally trade higher than GIAXXX so I'm thinking that the cutter would have just sent it to AGS.

Regardless, I'm sure it is a very lovely, lively stone! No wonder you are loving it. Can you take some pictures for us?

 

[Jumpin_Jacks]

Sure, a few I posted in LIW and a few more I took today. Still need to read the thread on getting arrows a little better, my macro setting is wonky. And as always, so much more sparkly in person!

 

[John P]

That's a pretty diamond and ring.

RE the discussion above, it may be useful to know that these links do not refer to AGS Platinum Light Performance grading.

I looked at the AGS cut tables http://www.agslab.com/docs/pbcg/AGSLProportionCharts.pdf which listed it as Ideal

Here is AGS's cut grading system: http://www.agslab.com/proportion-based-cut-grade.php

These correspond to the more lenient AGS 2D "Gold" proportions system. It's a system designed to mimic the GIA approach; using averaged 2D proportions to assign a predictive grade that's easier and not diamond-specific. Also, like GIA, that system permits polish and symmetry to be less than 'Ideal' and still earn the overall '"Gold" Ideal grade.

More here:
https://www.pricescope.com/communit...ags-certificates-can-experts-chime-in.129850/

It's impossible to know if your diamond really does fall into AGS 0 because rounding on the GIA report doesn't allow you to actually know what a few of those important values really are.

It would appear to be 'Ideal' in the Gold metric, based on estimates of minor-facet choices and consistency from the hand-shots. But there is no way to know if it would be 'ideal' in the 3D Platinum (light performance) metric without sending it in or running it through the AGS PGS.

My immediate feeling is that it probably does fall into AGS 0 as far as proportions because a cutter wouldn't just randomly cut those really nice crown and pavilion angle ratios without also probably intending to cut everything else within a nice set of proportions.

I concur, esp with the images (although that's my opinion and not scientifically conclusive). But I'd add that producers excel at gaming the system. It's astonishing how may 41.X PA combos with leakage are being produced now, simply because the 2D numbers are assured of falling into GIA EX. In terms of the global picture the final target is often 2D averaged numbers, without regard for craftsmanship beyond those basics.

Another issue here is that even diamonds with great proportions and symmetry can have facets that are slightly tipped, so internal reflections (and resulting virtual facets) are slightly off.

Bingo. Not for this example, but in the macro. Per the above.

 

[daz1]

Picked a great diamond the future fiance bought at a great local brick and mortar. I know GIA XXX doesn't equal AGS 0 in many cases, but how do I tell if I have an AGS 0 as well. I looked at the AGS cut tables (http://www.agslab.com/docs/pbcg/AGSLProportionCharts.pdf) which listed it as Ideal, is that it then or does it need further analysis to confirm? Links to photos of stone here: [URL='https://www.pricescope.com/community/threads/waiting-for-my-custom-set-how-did-i-do-on-stone-price.189700/..']https://www.pricescope.com/community/threads/waiting-for-my-custom-set-how-did-i-do-on-stone-price.189700/....[/URL]. BTW, I've seen and worn the ring around the house, goorgeous.

I guess answers here would help anyone looking for those GIA XXX that could be AGS ideal as well. Approx what % do you all gander of GIA XXX also fall into AGS ideal? Thanks in advance, PriceScope is a wonderful wealth of info

GIA 2146107353
HCA: 1.4

ROUND BRILLIANT
Measurements 5.84 - 5.87 x 3.65 mm
Carat Weight 0.77 carat
Color Grade F
Clarity Grade VS2
Cut Grade Excellent

PROPORTIONS
Depth 62.4 %
Table 56 %
Crown Angle 34.5°
Crown Height 15.0%
Pavilion Angle 40.8°
Pavilion Depth 43.0%
Star Length 50%
Lower Half 80%
Girdle Slightly Thick, Faceted, 4.0%
Culet None

FINISH
Polish Excellent
Symmetry Excellent

FLUORESCENCE
Fluorescence None

CLARITY CHARACTERISTICS
Clarity Characteristics Cloud

nice diamond. Do you mind telling me how much the main diamond cost you on its own as I am buying a similar one.. same size face but 0.75ct E vs1

 

[diamondseeker2006]

John, many cutters use GIA regardless of whether AGS would have granted an ideal grade, correct? Only a small percentage of diamonds are graded by AGS, is my understanding, so just because a diamond is graded by GIA does not necessarily mean it is inferior to AGS graded stones.

 

[John P]

John, many cutters use GIA regardless of whether AGS would have granted an ideal grade, correct? Only a small percentage of diamonds are graded by AGS, is my understanding, so just because a diamond is graded by GIA does not necessarily mean it is inferior to AGS graded stones.

Not at all. A diamond is a diamond. But I think I know what you mean...

A diamond is a diamond means that its specs don't change. Yet it can be graded differently by different labs.

That makes lab choice a massive matter of strategy by the producer, based on the target market and the collective specifics of the diamond. In a production of millions of carats, diamonds that are borderline XY color and/or clarity may be sent to a soft lab to upgrade those Cs, then released to a target market where that lab is viable. The sellers on PS don't promote paper from such soft labs, because it's well-known that the inconsistency and variability prevent meaningful deliberations online.

RE your post: GIA has many lab locations and is viable in all markets, globally. By comparison AGSL, with their single location, grades a fractional number and is rather limited to the USA market. When producers are determining labs, diamonds which could earn AGS 000 will indeed be sent to GIA (or NGTC or IGI HK in China...HRD in Europe...etc) simply because those reports are more known/viable in those target markets.

On the other side of the coin, there are diamonds which come to this market which might have initially been planned for AGSL, but it was discovered they would not achieve 000, so they became re-routed to GIA and earned EX.

Does that help?

 

[MissGotRocks]

John, many cutters use GIA regardless of whether AGS would have granted an ideal grade, correct? Only a small percentage of diamonds are graded by AGS, is my understanding, so just because a diamond is graded by GIA does not necessarily mean it is inferior to AGS graded stones.

Not at all. A diamond is a diamond. But I think I know what you mean...

A diamond is a diamond means that its specs don't change. Yet it can be graded differently by different labs.

That makes lab choice a massive matter of strategy by the producer, based on the target market and the collective specifics of the diamond. In a production of millions of carats, diamonds that are borderline XY color and/or clarity may be sent to a soft lab to upgrade those Cs, then released to a target market where that lab is viable. The sellers on PS don't promote paper from such soft labs, because it's well-known that the inconsistency and variability prevent meaningful deliberations online.

RE your post: GIA has many lab locations and is viable in all markets, globally. By comparison AGSL, with their single location, grades a fractional number and is rather limited to the USA market. When producers are determining labs, diamonds which could earn AGS 000 will indeed be sent to GIA (or NGTC or IGI HK in China...HRD in Europe...etc) simply because those reports are more known/viable in those target markets.

On the other side of the coin, there are diamonds which come to this market which might have initially been planned for AGSL, but it was discovered they would not achieve 000, so they became re-routed to GIA and earned EX.
Does that help?

This was exactly the scenario I was talking. If it COULD have gotten the AGS0 grade, it makes sense that it would have been sent there in the first place. However, as you point out, all markets (overseas) might not seek AGSO anyway so GIA XXX would be their target.

At any rate, the stone looks beautiful and I am happy you are happy with it. It looks to be a very nice stone. Since we don't wear the paper from the lab, just enjoy your beautiful ring!

 

[Jumpin_Jacks]

Thanks John, definitely a compliment coming from you! I ditto your explanation on the marketing and lab, kind of like, if it's AGS ideal material, grade it there with a smaller audience with premium or go def GIA XXX with a larger target audience. Also then there's just plain the best it could get is GIA XXX. No way to tell what happened in my stone's case, but very interesting!

Daz: Purchased May 2013, $4,300 at Liberty Diamonds in Irvine, CA. Width is 2mm (1/2 eternity), .97 total ER TCW with melee. Paid cash and with setting and matching wedding band $6800 total. Not sure if diamond prices have gone up since then.

MissGotRocks: Thanks! I'm loving the high (or absence of) color and can't wait to rock it around town!!

 

[diamondseeker2006]

John and MGR....I was referring to MGR's earlier comment that stones that potentially could get AGS0 would have been sent to AGS. I didn't believe that was really true. There are still cutters who believe GIA is the premier grading lab in the world and they send all their stones to GIA, period, even for the US market. We are all familiar with AGS due to some of the H&A vendors on PS using AGS for their inventory stones, but I don't think everyone in the diamond world perceives AGS as superior and relatively few stones are graded by them percentage wise. Therefore, we cannot assume that stones within GIA EX that fall into ideal cut parameters are lesser stones than those graded as ideal by AGS or that they would have been sent to AGS had they been able to get 000. I think that is absolutely true of vendors that deal in AGS H&A stones (that they only send stones there that will get 000), but that is a small part of the overall diamond market.

 

[Jumpin_Jacks]

John and MGR....I was referring to MGR's earlier comment that stones that potentially could get AGS0 would have been sent to AGS. I didn't believe that was really true. There are still cutters who believe GIA is the premier grading lab in the world and they send all their stones to GIA, period, even for the US market. We are all familiar with AGS due to some of the H&A vendors on PS using AGS for their inventory stones, but I don't think everyone in the diamond world perceives AGS as superior and relatively few stones are graded by them percentage wise. Therefore, we cannot assume that stones within GIA EX that fall into ideal cut parameters are lesser stones than those graded as ideal by AGS or that they would have been sent to AGS had they been able to get 000. I think that is absolutely true of vendors that deal in AGS H&A stones (that they only send stones there that will get 000), but that is a small part of the overall diamond market.

Is there an article or something in a nutshell that explains the mine to consumer chain? I know something about people who bid on rough stones then off to be cut, but that's about it. Does the cutter determine who grades? I was thinking the vendor but with most stones sold in a database, that can't be the case. FWIW, my stone was in my jeweler's possession at the time of my first visit, we came back the next day to finalize setting details and put the deposit down.

**EDIT** I googled the mine to consumer chain, still wondering about who determines what lab it goes to for grading..

 

[John P]

John and MGR....I was referring to MGR's earlier comment that stones that potentially could get AGS0 would have been sent to AGS. I didn't believe that was really true.

Not in a blanket-sense. As I said in my prior post...

RE your post: GIA has many lab locations and is viable in all markets, globally. By comparison AGSL, with their single location, grades a fractional number and is rather limited to the USA market. When producers are determining labs, diamonds which could earn AGS 000 will indeed be sent to GIA (or NGTC or IGI HK in China...HRD in Europe...etc) simply because those reports are more known/viable in those target markets.

On the other side of the coin, there are diamonds which come to this market which might have initially been planned for AGSL, but it was discovered they would not achieve 000, so they became re-routed to GIA and earned EX.

It happens both ways.

There are still cutters who believe GIA is the premier grading lab in the world and they send all their stones to GIA, period, even for the US market.

Regardless of beliefs, much of this involves economics. I know diamond producers in every major cut-center and none send everything blindly to a single lab. GIA generally gets the diamonds of max value. EGL tends to get a lot of diamonds destined for commercial showrooms in the west, as does IGI. Our operation is 100% cut-focused, so every diamond has the same cut-proposition, but we use the lab which is best-suited for a diamond's target-market; currently AGSL for our USA dealers and GIA for our Asian clientele.

We are all familiar with AGS due to some of the H&A vendors on PS using AGS for their inventory stones, but I don't think everyone in the diamond world perceives AGS as superior and relatively few stones are graded by them percentage wise.

AGSL grades something like 1% or less. In terms of perception, AGSL is known as fast, reliable and strict but they have nowhere near the name-recognition of GIA/EGL in mainstream jewelry stores. That lack of gravity works against them, and makes my day-job harder.

The main strategic advantages of AGSL are the single/small lab-location, which makes them extremely consistent, and their 3D cut grading metric which is stricter and more sophisticated than any other current system. This system makes them a good fit for online sales, which is ironic since they ban exclusively-online sellers from joining the society. That strictness is a two-edged sword, though, as it limits the number of diamonds that will ever be sold with AGS paper: No one wants to try and sell an AGS3-4 diamond, so diamonds which go to AGS but fall short of Ideal are frequently re-submitted to a second lab (GIA or other) and marketed with better-seeming paper.

Therefore, we cannot assume that stones within GIA EX that fall into ideal cut parameters are lesser stones than those graded as ideal by AGS or that they would have been sent to AGS had they been able to get 000.

The problem is that we can't know if a diamond "within GIA EX" will have AGS 0 performance parameters or not. GIA doesn't present enough data on the grading report to know. The only way to know is to send it to the lab, or run the grading software on a scan of the diamond. Without doing that we can only speculate.

I think that is absolutely true of vendors that deal in AGS H&A stones (that they only send stones there that will get 000), but that is a small part of the overall diamond market.

I've seen the term H&A used a couple of times here: I should mention that AGS doesn't grade H&A. In fact no USA lab yet grades cut-precision or even simple 2D "H&A patterns" - so it's currently a non-factor in terms of lab choice for H&A diamonds in the USA.

 

[John P]

Thanks John, definitely a compliment coming from you!

You're most welcome. The shots I like best are the top and bottom pics; where you have it in both direct light and shaded light, yet all the mains are bright. Nice subject and nice camera work.

Is there an article or something in a nutshell that explains the mine to consumer chain? I know something about people who bid on rough stones then off to be cut, but that's about it. Does the cutter determine who grades? I was thinking the vendor but with most stones sold in a database, that can't be the case. FWIW, my stone was in my jeweler's possession at the time of my first visit, we came back the next day to finalize setting details and put the deposit down. **EDIT** I googled the mine to consumer chain, still wondering about who determines what lab it goes to for grading..

The path from mine to consumer can be an Alice In Wonderland of detours and wonders.

It begins with a handful of mining houses and rough distributors who control the excavation and distribution of the world's supply of diamond rough. These houses have relationships with sightholders/secondary sellers who purchase rough in bulk. Some of these secondaries sell it down the chain, some have cutting operations, some do both. Then you have a host of polished diamond manufacturers of all sizes. They are cutting materials acquired in purchases, at tender, in trade, etc. Some are small cutting operations, others produce many millions of carats annually.

With some large producers the choice of lab may be pre-determined depending on the vertical integration that entity has with buying organizations. Finlay, Sterling, Zale Corp and Buffett are examples from the USA. In China you have CSS and CTF. The productions for these companies serve thousands of stores in the end and ultimately involve finished jewelry as well as loose diamonds to be graded. These productions may have volume-arrangement with specific labs.

Other manufacturers supply international wholesalers who, in turn, serve brokers, chain stores and regional wholesalers in different world markets. This is where the choice of lab (or not) becomes strategic.

How are the decisions made? Generally it's all about economics. You're in a place (Pricescope) where there is notable emphasis - from participating pros and enthusiasts alike - on ensuring reliability and beauty, but in the world-at-large it's a bit different.

I remembered this post by Neil Beaty from long ago. It's a bit dated but still accurate. I like to paraphrase the part in bold when someone asks me this question IRL.

1) Cutters and dealers who are trying to maximize their profits (which is all of them) will choose their labs strategically. The decision is not necessarily being made with the objective of providing you with the most accurate shopping information.

2) ‘Borderline’ stones, tend to go to the labs with more liberal grading policies.

3) Buyers are more tolerant of variations with the second tier labs. A ‘certificate’ that is off by a grade or 2 is much more acceptable from some labs than others. This can be useful to the dealers. Many will describe this as a feature because you get a report with a higher grade on it for the same or less money.

4) Most GIA and AGS grading reports come with a cut grade where most EGL reports do not. Dealers may not wish to be advertising this particular feature.

5) The ‘best’ stones, meaning the ones that the dealer hopes to sell for a premium price because of attributes other than color and clarity, tend to go to the higher status labs. Stones where the lab reported color and clarity are the primary sales characteristics tend to go to the less expensive and/or more lenient labs.

6) Cutters and dealers have access to many different markets and they are not all the same. Certain marketplaces are conducive to presenting stones as commodities while others involve more specialized marketing.

The path of a stone from the mine to you was not chosen randomly and it wasn’t chosen by you. This choice is being made by some clever people who are working on razor thin profit margins that can vary considerably depending on the results. If they think they can make more money with that particular stone by sending it to a different lab and using a different retailer, there’s a pretty good chance that this is what they’ll do.

So what’s a sensible customer to do? Buy diamonds, not paper. Use the lab documentation to support or refute the expert advice from your dealer, not as a substitute for it. Choose your dealer first, then the diamond, not the other way around.

Original post by DenverAppraiser:
https://www.pricescope.com/community/threads/ags-gia-vs-egl-and-aga.43102/#post-617690#p617690

 

[Jumpin_Jacks]

Excellent, thanks John!! Appreciate your time explaining the cert aspect, very interesting especially some of the points you linked from Neil Beaty

 

[Texas Leaguer]

Rather than try to add to John’s excellent breakdown (I’ve got nothing!), I will just try to amplify a couple of takeaway points from the discussion, which many consumers attempt to understand.

The AGS light performance based grading system is a 3D system that accounts for the influence of every facet of the diamond. It is the most scientifically sophisticated system on the planet, as well as the least forgiving. That is why a platinum cert from AGSL is the ultimate pedigree for a shopper who is interested in diamonds of the finest cut quality.

The diamond is the diamond, no matter which lab does the reporting. So, a GIA Triple Ex certainly could be an AGS0. And, armed with the 3D scan of the diamond and the AGS LP Software, it is possible to determine how it fares in the AGS LP analysis. That said, it still is not “official” unless the diamond is actually graded by AGSL as the scan has to be verified and polish and symmetry graded Ideal by a different set of human graders.

While AGS is a “niche” lab, their value has grown with the information age. The importance of cut quality has been underscored by a number of excellent pricescope vendors, but it is a movement on a broad scale.

 

[diamondseeker2006]

Thanks, John! I, of course, understand all that. I was just trying to get at that elusive number of the 1% of diamonds that are graded by AGS, and the fact that the majority of the "best cut" diamonds are not automatically sent to AGS. I appreciate AGS and currently have three stones graded by them myself. But I did have a GIA graded stone that had amazingly tight cut according to a helium scan (and was designated H&A according to the images), and that cutter (manufacturer) only used GIA for their grading. It scored 000 on AGS software and was later regraded by AGS as 000 and one color grade higher, which worked out really well for me when I sold it! I just do not like the assumption that we see here sometimes that says that a diamond is probably not up to AGS standards because it was sent to GIA for grading and was just trying to correct that misconception.

(On this topic, a friend told me the other day that her AGS000 branded H&A diamond was regraded by GIA one color grade lower and got only 2 Ex!!!!)

 

[Texas Leaguer]

Thanks, John! I, of course, understand all that. I was just trying to get at that elusive number of the 1% of diamonds that are graded by AGS, and the fact that the majority of the "best cut" diamonds are not automatically sent to AGS. I appreciate AGS and currently have three stones graded by them myself. But I did have a GIA graded stone that had amazingly tight cut according to a helium scan (and was designated H&A according to the images), and that cutter (manufacturer) only used GIA for their grading. It scored 000 on AGS software and was later regraded by AGS as 000 and one color grade higher, which worked out really well for me when I sold it! I just do not like the assumption that we see here sometimes that says that a diamond is probably not up to AGS standards because it was sent to GIA for grading and was just trying to correct that misconception.

(On this topic, a friend told me the other day that her AGS000 branded H&A diamond was regraded by GIA one color grade lower and got only 2 Ex!!!!)

DS, I understand what you are saying and it is important to keep a balanced view of the AGS vs GIA discussion. The market perspective that John laid out and the various dynamics and calculations that go into determining which labs will be used for which stones are important to understand. While much more is known on the consumer level today regarding the importance of cut quality, yield and economics are still primary considerations at the producer level. Because GIA is so well known and well respected they are in the driver's seat by default. AND because their cut grade system is more forgiving, cutters have more options to make Triple Ex and retain weight. That ensures that they will be entrenched. There were very specific business decisions on the part of GIA in terms of how demanding they wanted to make their cut grade system, as it has far reaching implications for their constituency.

To understand how yield still trumps beauty at the producer level today, you have to look no further than the princess cut. Imagine what kind of backlash there would be in the industry if GIA came out with a princess cut grade system as rigorous as AGS. Even a forgiving system would significantly devalue a huge portion of the current collective inventories.

So if there is an impression that a GIA EX is generally not as good as an AGS0, there is some basis for that sentiment. Many cutters are cutting nice GIA rounds today as a result of GIA launching their cut grading system. And a small portion of that cutting is geared towards the middle of the bullseye, in part because of the recognition that there is a market for the best of the best.

The consumer market would greatly benefit from GIA releasing a cut grade system for other shapes. Don't look for that to happen any time soon, but do look for cutters to continue cutting EX EX with lousy light performance as a result.

Congrats to AGS for having the vision to build a lab dedicated to cut quality analysis. They are shining a light that consumers are becoming illuminated by which has begun to change the calculus at the producer level. It would be better if AGS was bigger and had more clout, and then maybe change would come at a faster pace.