AGS new cut grade system early 2005

[Garry H (Cut Nut)]

Rap news

AGS Introduces Fancy Cut Grading System

By RapNews Posted: 9/14/2004 9:09 AM

(Rapaport…September 14, 2004) The American Gem Society has announced that it will launch a new fancy-cut diamond grading system in the first quarter of 2005 and will also modifiy its existing round brilliant cut-grading scale. These changes take place after five years of research and the introduction of new technology which uses three-dimensional imaging and optical ray tracing to evaluate a diamond''s cut.

The first fancy cut to be graded by the AGS will be the popular square princess cut, and more cuts are expected to be added later in 2005. With regards to the round brilliant cut grading scale, although the methodology for determining potential AGS Zeroes has changed, the AGS standards do remain the same, as does the AGS zero-to-10 scale. AGS Triple Zeroes will continue to designate an ideal grade, but the new subcategories now will include light performance, proportion factors and finish. The new cut-grade system allows for a net increase of 37 percent for potential round brilliant AGS Zeroes.

Diamond Quality Documents incorporating the changes in the diamond grading scale for square princess and round brilliant cuts will be available during the first quarter of 2005 and in the middle of that year, AGS members will have the opportunity to acquire software and training to perform their own cut analysis.

 

[Paul-Antwerp]

Kudos to AGS for incorporating their research into a new grading system, and especially for arranging this relatively fast.

Live long,

 

[Paul-Antwerp]

If I understand this press release correctly, the cut will still be divided into three subcategories:

- polish and symmetry will be combined in the new factor: finish
- proportions will remain as a factor, but will probably have new boundaries.
- light performance is a new factor, which is probably not based on metrical parameters.

Nice,

 

[Regular Guy]

Just so I'm clear about what the 37% means...would that suggest, then, for example, that when given a sample of 1000 diamonds, if previously 100 of them would have made AGS000, now it would be 137?

 

[Paul-Antwerp]

No no, it means that we can charge 37% more for the new AGS-0.

Just joking. Honestly, I do not understand that sentence.

Live long,

 

[oldminer]

Yes, approximately 37 percent more diamonds will fit the AGS 0 model than at present. No doubt, most of them will have a great light performance, much more consistent with eachother than under their old system, BUT not all of them will truly be as well cut if one looks at the craftmanship component of cut. While AGS has fixed their steep/deep issue, they have opened Pandora's box with shallow crown stones that have somewhat deeper pavilions. These diamonds Garry and AGS assure us will perform very well, but will they be as pleasing a product? They will cost less, up to 20% less to produce, as less rough goes to waste, but will they be as superior a product as a near Tolkowsky cut? It may be easier to convince the public than to convnce me or expert cutters. I view the AGS 0 system as having been too liberal before and, although changed, still overly liberal and excessively commercial. If you want a superior diamond, an AGS 0, under the present or the new strategy may not get you the very best possible stone and that's regrettable. An AGS 0 will be a very nice diamond, but may not be a top stone in every respect. What's the point of seeking the ultimate quality when it remains undefined or mixed up with 2nd and even 3rd tier gems?




Performance is one element of Ideal.


It takes more than light performance to create an "Ideal" diamond although there is no question that without light performance being high, a diamond can't be an Ideal cut. There are people who will insist that light perfromance is all there is to "ideal". I say that is a wrong opinion.




Finish is a second component: The concept of proper facet shape, correct facet placement, facet matching, and a pleasing symmetrical outline are four elements necessary to consider and grade as "excellent" if one is to have an "Ideal" stone.



Parameters of cutting are the third component.


They define a diamond of proper depth to width ratio, sufficent crown angle for durability, sufficient but not excessively thick or thin girdle thickness, and the proper table and culet size range. These important aspects are not part of "performance" or "finish", but are essential, in my view, to defining the "Ideal" diamond.




It would not be a difficult task for my lab to adopt using only the AGS system for grading, but I just feel that it is not the right system. Rather than just criticize, we are hard at work to bring proven scientific light performance information, combine it with AGA Cut Class grades and then include a very rigorous "finish" grade for the consumer and the trade. Its easy to criticize and have nothing positive to offer. We hope that in a few weeks we will have some very viable and less problematic solutions. The "Light Performance" and "Finish" grading devices and software will be made available via Imagem, Inc. to all qualified labs and interested parties as part of their business plan. I have freely allowed the AGA Cut Class system to be accessed by anyone interested for many years, and hope to continue to offer it for free. AGA is going to put all three components into upcoming diamond reports. I think we will have a superior service to offer those who want the very best. We'll see how it goes.

 

[Garry H (Cut Nut)]

I think this rough black ovelay might explain the AGS +37%.

The white box is the current Crown and Pavilion range overlain on the HCA.
The black line is a possible range AGS might use (please do not take this as gospel, because although Peter Yantzer and Jose' Sassian shared an enormous amount of info at the cut conference in April, they did not give us the actual proportions).

Dave I think you have a slight case of expert blindness. I have sold many diamonds with these shallower crown angles (and bigger spreads) over the years to consumers who have had traditional ideal cuts (with smaller spreads) sitting right beside them. The consumers have made their own choice.

From my experiance, given that the shallower crown deeper pavilion diamond - more than 1/2 the consumers will buy that stone.

You are assuming that consumers have experiance and that they will say "this diamond does not look like my other ideal-cuts".

But Dave - how many people own ideal-cuts? And how many so called ideal-cuts really look fantastic?

I think AGS's new system will fly

 

[Paul-Antwerp]

I beg to disagree with your view, David.

I think that the parametrical area, of which the proportions can score the new AGS-0, is about 37% bigger than the area for the old AGS-0. This does not necessarily mean that it is easier to cut, because it possibly is a long narrow area, that is easier to miss, when compared to a rectangular box with a smaller surface.

When you say that some of the new AGS-0 cost about 20% less to cut, you are talking about the current situation. With this possibility, demand for this rough will increase, and the rough dealers and producers will quickly understand that they can easily raise prices for this rough. Within no time, this 20% difference will disappear.

All in all, I think that definitely in a first stage, we will see much less AGS-0-stones. Even in the long run, I think that less diamonds will be AGS-0. At the same time, I suppose that AGS-1 and AGS-2 will get a clear value, which now is non-existent.

I agree with you that different AGS-0-stones will look differently in the new system, and I do not know if that is such a good development. Therefore, we will not change the current Venus-by-Infinity-parameters. I think that it is also important to keep that consistency in your production, and to show that to consumers.

Anyway, this new system is an exciting development, and I cannot wait to hear more about it.

Live long,

 

[Paul-Antwerp]

Garry, we were partially thinking alike again.

Thank you for that illustration. Now, make that black-lined area just slightly narrower. Suppose that you have to shoot at the black-lined area from a distance, isn't that more difficult to reach than the nice rectangular white-lined area?

This clearly illustrates my idea that even with a bigger area to shoot at, it might be more difficult to get it.

Now imagine a cutting operation: it is doable to adapt to a new set of proportions, and to aim for that, so after a period of adaptation, you can get organized to reach the same number of ideal-proportions. But at the same time, you have to take a new parameter into account, because light performance now also needs to be ideal in order to get AGS-0.

Frankly, I think that we can really add 37% to the price in the new system, because of less availability of AGS-0.

Live long,

 

[Garry H (Cut Nut)]

Paul we know that you could shoot any tiny spot on that chart.

But Dave - surely the fact that cutters could save 20% of economic value underpins what I have been saying all these years.

We have wasted billions of dollars of diamond every year for the past few decades by forcing cutters to cut to a narrow target range!!!!

 

[Paul-Antwerp]

I know I can, Garry, and so can a number of my colleagues.

But you would be surprised how many of my colleagues will continue to aim at the wrong target for months and maybe years to come. (Remember that sightholder, who asked you last week for the current proportion-borders of GIA?)

Allow me to make a bold prediction: in the year after the introduction of the new AGS-system, the lab will issue 50% less AGS-0-reports compared to the previous year.

Live long,

 

[Garry H (Cut Nut)]

Hmmm.
I think AGs have a very effective communication track record with manufacturers.
I have personally been involved in some cases and AGS have been exceptionally responsive.

 

[kevinng]

So... what will happen to those people who bought an AGS0 in the past... but no longer own AGS0 with the new grading? Can they not say that they relied on AGS' report for their purchase, and demand for some sort of compensation?

 

[Paul-Antwerp]

I agree that AGS is very open in their communication, Garry.

But I know the people that should be listening to their information. And you will see: A spoken word is not necessarily a heard word.

Kevin, AGS gives a report according to their rules and knowledge at the point in time of the report. They are not responsible for the pricing. Many of the vendors here on Pricescope clearly know the difference between a current AGS-0, and one which will also be AGS-0 in the new system. Pricescope as such is one of the pioneers, who have made AGS realise that something was wrong with the old system. If one has bought an AGS-0, based upon Pricescope-advice, he will have no problem with the new system.

Live long,

 

[JC]

I think that's GREAT! It's will be nice to see a fancy shaped diamond that has been graded by AGS. They already provide more information on the grading report when it comes to round diamonds. So maybe they will include more information for fancy shaped diamonds when comparing the new report to GIA graded documents. That will only help the selling of fancy shaped diamonds. So that's good news. Thanks for the info....

 

[diamondlil]

----------------
On 9/16/2004 5:14:46 AM kevinng wrote:

So... what will happen to those people who bought an AGS0 in the past... but no longer own AGS0 with the new grading? Can they not say that they relied on AGS' report for their purchase, and demand for some sort of compensation?----------------

My interpretation is that AGS has broadened their parameters for AGS-0 so there will be more stones (including the ones which already have that designation) that will now be given the AGS-0 classification. Is that correct, experts?

I am glad to hear they will be doing fancy-shape grading, and I am anxious to see how it compares with the current AGA classes. You are right, JC, I think that will help with selling fancy shapes.

DiamondLil

 

[oldminer]

As always, Garry is very convincing and well informed. I am going to hold my ground, for the time being, but promise to keep a very open mind on the subject. I know there are many choices and many possibilities. No doubt, consumers will have less "expert" prejudice and I do respect the power of the free market to make intelligent decisions for all of us.

While I am busy at work putting the AGA systems in line with light performance equipment and readings, I will also attempt to automate the AGS approach so that my lab can give either or both results. I don't care if I am right or wrong, but I do care that the trade and the public are well served. I don't doubt the good intentions of AGS and I'll seek out a reasonable approach to any problems that arise. That's the style of the way I do business.

It will be a very exciting period of time for the various Cut Nut's of the world!

 

[JohnQuixote]

----------------

My interpretation is that AGS has broadened their parameters for AGS-0 so there will be more stones (including the ones which already have that designation) that will now be given the AGS-0 classification. Is that correct, experts?

DiamondLil----------------

Lil,

Some diamonds that used to pass as AGS0 under the old system will now fall outside that range, were they to be re-graded. However, as Paul noted, those who have purchased current AGS0 cuts using the best advice available here on Pricescope should have naught to worry about.

(PS: Dear Whiteflash “A Cut Above” owners - all ACAs are within the ‘safe range’)

 

[Garry H (Cut Nut)]

here is another article from Professional Jeweler.
It has some obvious mistakes in it. Can anyone pick them?

http://www.professionaljeweler.com/archives/news/2004/091304story.html
AGS Unveils Cut Grade Plans

American Gem Society Laboratories (AGSL) lab reports will include new and improved cut grades for round diamonds starting in the first quarter of 2005. For the first time, AGS will also offer a cut grade for princess cut diamonds. Round and princess cut diamonds constitute the most popular diamond cuts among U.S. jewelers and account for a majority of diamond sales.

"The format of the lab reports will remain the same as in the past, with final diamond grades listed on the familiar scale of 0 to 10," says Peter Yantzer, AGSL executive director. "The changes incorporate the findings from our most advanced cut grade research on round brilliant diamonds and princess cut diamonds. The bottom line is that it provides retailers with greater assurance about the solidity of their cut grade. It also provides them with additional choices." Further good news for cutters and retailers is that the research findings enlarge by 37% the potential field of candidates for diamonds that can achieve a "0" grade (AGSL's highest cut grade for a diamond). The addition of the princess cut grade also increases a retailer's selling opportunities.

Ruth Batson, executive director and CEO of AGS, says the incontrovertible nature of AGS findings also protects the consumer, which is one of the basic pillars of the American Gem Society.

AGS fancy cut-grading research is composed of an AGS task force as well as outside industry experts and physicists. It started almost five years ago, and is funded in part by JCK magazine.

Larger Field of Candidates

"We want retailers to understand that the known format of the reports supported by our findings will provide a very positive opportunity for retailers," Batson says. "The research is reassuring and exhilarating in that our methodology provides great promise for other fancy cut grades in the not too distant future," Yantzer adds.

AGSL research incorporates three dimensional imaging and optical [light] ray tracing to evaluate cut. AGS says their conclusions help underscore Marcel Tolkowsky's own two dimensional diamond math based modeling, (Diamond Design) postulated just over a century ago. His work centered on round brilliant diamonds with 53% tables; 60-61% total depth; 16.2% crown height; 43.1% pavilion depth and girdle thicknesses of 0.7 to 1.7%. Crown angles of 34 degrees, 30' and pavilion angles of 40 degrees, 45'. These factors, he theorized, were necessary to make an optimum cut. Since his day, cutters have used and modified Tolkowsky's guidelines to suit their needs, mostly by lengthening or shortening lower girdle facets, and by enlarging (or decreasing) the table facet percentage.

"Tolkowsky was right, really," Yantzer says. He notes that Tolkowsky's theoretical diamond sits smack in the middle of AGS' list of potential candidates. Three dimensional research and optical ray tracing was not available to Tolkowsky, however, and AGS research finds that diamonds with tables between 47% and 57% can also achieve AGS "0" grades with varying degrees of success, depending on what compensations were made to other aspects of the diamonds' cut angles to ensure proper light return, or brilliance. This discovery allows cutters and retailers more flexibility to adjust for societal and cultural preferences (some people prefer more fire, others more scintillation.)

AGS also says that it will soon make ray-tracing software available to member retailers who want to better understand the mathematical reasons for light return, as well as see how a given diamond performs. The metrics are repeatable and accurate, taking into account light dispersion, leakage, direction of light return, brightness, contrast and fire, among other factors.

For retailers, the findings translate to added sales of AGS "0" diamonds whose footprint or outline may be the same, yet in which the weights are considerably different. "For example, a 6mm stone may weigh either 1.40-ct or 2.00-ct, and because of cost considerations, a customer may want to choose the 1.40-ct stone," Yantzer explains.



Robert Weldon, G.G.

 

[valeria101]

Is the AGS going to state the new rule with a range of crown and pavilion angles as before? Or some crown&pav relation?

I am not sure if the drawing shows the problem well: but... using a range for each of the two angles (the old way) one can obtain a square on the chart.

If the new ideal range is as Garry drawn it, than it is not feasible to define it in the old way - otherwise the resulting rectangular area will go way outside the desirable range (shown left) or… you need allot of little squares (right) each for a certain narrow range of crown and pavilion angles (right). The first version leaves undesirable areas inside the advised range, and the second version yields a hard to justify grade with debatable no-go areas. IMO.

 

[Garry H (Cut Nut)]

Life was not meant to be easy Ana.

The little boxes will be the go.
Shhh Paul.

 

[Garry H (Cut Nut)]

BTW if anyone wants to play with very small tables etc on HCA - you will find it still works - but there are no charts because we never made them.

This is a 47% table which AGS have said they will go down to!

 

[oldminer]

Garry:

Would you alter one of the light charts to show the AGA 1A and 1B range for me and the readers, please. I'd like to see how it compares to the new and old AGS 0 range.

The light performance grading we will be doing shortly will NOT be in BOXES, but will flow from directly measured light in a controlled environment. Because I trust the AGS's integrity, I would not be at all surprised to see AGA top light performance stones within the AGS sausage shaped high performance zone, or within most of their box shapes. I just can't be sure about that at this time.

Thanks..

 

[Garry H (Cut Nut)]

As you know Dave, I believe that what HCA does is attempts to report what happens in nature with round brilliant cut diamonds (within my all rounder, but limited, human capacity). After all that is what physics is - the study of our physical environment.

I see no reason why AGS and your new Imagem systems would not arrive at similar conclusions - beacuse we are all studying the same physical stuff.

I will put your charts onto my chart tomorrow (a bit tiddly just now - Japanese Friday night). But the issue I have with your approach is it is wasteful to cut away all that beautiful diamond to arrive at such a restrictive, all be it a guaranteed beautiful, diamond.

I do not believe AGS will have a bad system - they will have a better guarantee of quality than HCA - but they too will be wasteful because they will make no compromise for slightly shallower diamonds.

Peter yanter said they want every diamond to look good from 8 inches (20cm) - I think 14 inches (35cm) is close enough. AGS also do not factor in spread - i give a bonus for a diamond with a bigger spread - why? Because in my experiance a consumer will pass over a slightly better cut stone for a larger spread diamond, so long as the diamond is bright.

 

[oldminer]

Garry: Thanks for your response. I have no idea what "tiddly" is, or "Japanese Friday night" for that matter. But, I do appreciate that you'll post the charts tomorrow.

In a way I agree that I would not want to cause wasteful cutting and I think 8 inches is a decent compromise for human viewing. It seems a lot closer than a normal "look" at a diamond, but further away than close, expert scrutiny, too.

The public does like a larger, rather than a smaller diameter stone. This is a general preference that I agree with. When it comes to the "quality" of the cut, more than human preference or visual appearance matter. Cutting is a skill and it is based partially on the characteristics of diamond. Diamond has primary limitations due to refractive index, brittleness, and cleavage. Only within certain bounds are diamonds finely cut. There are definitely pretty large zones of high light return diamonds populated by less well crafted diamonds, and some of these may prove very good sellers. The price will be favorable and what does the consumer really know? They rely on us to assist them honestly.

I won't buck the market with an unworkable or unrealistic system, but will work to make changes that truly fit the best range of cut AND light perfromance. I won't make an AGA system compromise the word "Ideal" for merely "very good", but where the truth is will be sufficient for the careful shopper.....

Keep on tiddling....??

 

[Greentree]

"But the issue I have with your approach is it is wasteful to cut away all that beautiful diamond to arrive at such a restrictive, all be it a guaranteed beautiful, diamond." - Holloway.

That is the crux of the matter. I believe David is saying 100% light return is necessary but not sufficient to warrant the title Ideal Cut. Dimensions and proportion must be considered too. Do you recall the "Golden Ratio" found in geometry. Its been known for centuries that geometrical shapes which incorporate the Golden Ratio into their dimensions are somehow more pleasing to the eye than those shapes which deviate away from it.

I don't know if the Golden Ratio can be found in the Ideal Cut diamond David has in mind, but I think the principle is the same. Certain proportions are pleasing and others are not. I strongly suspect the Golden Ratio would be almost mandatory for an Ideal emerald cut diamond due to its rectangular shape.

 

[Garry H (Cut Nut)]

I thought the diamond equivalent was 60:60 GreenTree?

As you know my HCA system recomends 60:60's with the right crown and pavilion combinations.

I have also cut diamonds with very small tables and they were kbock outs. We cut them for a new mining venture.

sure they have smaller tables - but they looked very firey.

 

[glitterata]

Not qualified to address the fascinating technical stuff, but by "tiddly" and "Japanese Friday night," I suspect Garry might mean he's been indulging in a cup or two of sake?

 

[Greentree]

Over the past couple of years you have posted several examples of diamonds that have excellent light return but also bizarre proportions. I think the point you were making is there exists a rather wide range of angle/percentage combinations that result in 100 or near 100 percent light return. What David seems to be arguing against is allowing the term Ideal to encompass such a wide range of values.

As you know, I'm partial to EightStars. I've noticed that all of them have the same HCA score and, significantly, all fall in a tight circle located at a particular point on the HCA graph. (It's no surprise. Proportionally, EightStars are clones of each other).

During its development the Japanese had to decide what their vision of the perfect round brilliant diamond would be. After due consideration, they, in essence, picked a point on your graph and defined it to be the "EightStar point" --if you will. This point defined a diamond with all the characteristics that in their view the perfect diamond should have.

The concern is allowing a wide range of values to be designated as Ideal means that just about any point in the desirable portion of your graph will suffice. Diamonds will be marketed that fall all over the place. The notion of Ideal will consequently become difficult to describe. It's too big a bull's-eye.

 

[Garry H (Cut Nut)]

But the market will work it out - just like their are ideal cars that have soft tops and ideal 4x4's