ASETs and fancy cuts

[Texas Leaguer]

DiaGem--
Setting that diamond to take full advantage of the light entering below the girdle would be very important information for the owner of that kind of diamond, or any other that was designed in this way.

Prongs would block, maybe, 30% of light entering just below the girdle?

When set, would those areas in the corner of the table not be darker than what's in those pictures?

this s a great question!
In my experience, many diamond designs are affected by light entering the pavilion- particularly in the setting.
I have not noticed it specifically affect the prong areas as you suggested- however I have never set a diamond like the new one Yoram posted. (yet )

That's exactly the point of light designed Diamonds, their purpose is to emphasize a specific appearance, in this case a solid red (Aset) center star. Sure, it "might" have an effect but who says its negative? Don't all settings have the potential to affect? Let's not forget it's still a respectable AGSL 1 for LP (0.91 deduction vs a 0.49 needed for a 0 grade) and will probably earn 0's for both symmetry and polish.
Based on our tests, it's not that sensitive as you might imagine.

How much of that deduction is Brightness deduction versus Leakage?

MD, Here is Yoram's statement on the grading metrics from his earlier post:

This specific design was analyzed by AGSL on its 3D file, it got deductions as you estimated very well both for brightness 0.60 & leakage 0.31. (Based on memory as I am out of the office). A cumulative deducted score of 0.91 (e.g. LP score of 1).
It's a pity as this cut performs amazingly and also displays a controlled play of light based on its design. The problem is the AGS 1 grade can't be translated into a top cut simply because it's grade is based on that "bad" leakage where the pics and asset clearly show it's not.

Maybe if we could have the algorithm numerical value listed on the grading reports we could have a better chance utilizing the AGSL grading system for other cuts rather than just triple 0's.

I think consumers will be better informed if we can show them how the grade was set.

You both have alluded to the actual AGSL grading metrics which I think is very important to keep in mind in this discussion; ASET is only the graphical representation of the angular spectrum that the diamond is reflecting. While an integral part of AGS PGS construct, it is not the grading system per se. The system, through calculations by its ray tracer, assigns numerical deductions for deficits in brightness, contrast, leakage and dispersion. And since those deductions are cumulative, you can have small deficits in each characteristic that add up to a grade deduction.

One implication of this is that it is possible to see alot of red in an ASET and not get AGS 0. Conversely, it is possible to see a relatively large amount of green in ASET and still get AGS0 (depending on the shape).

 

[Garry H (Cut Nut)]

HI Serg,


By the way- I want to be clear that I learn a lot fro these discussions. I respect the work you and Garry do. I completely respect that you are in the business of figuring out how to make diamonds look best in your view.

Wrong David, very wrong.
Our work is to make diamonds more attractive to consumers.
To move our industry from turning magnificent rough diamonds produced by nature into commodities.
As the ex head of Alrosa once said to a diamondtaires association:
"We treat diamonds like glass and Swarovski treat glass like diamonds."

You may have noticed that many times Sergey and I do not agree on certain aspects. But we agree on an end vision. And it is not about convincing the world to like the same thing as us.
We want to info from crowdsourcing consumers data to drive cut innovation!

 

[Garry H (Cut Nut)]

You both have alluded to the actual AGSL grading metrics which I think is very important to keep in mind in this discussion; ASET is only the graphical representation of the angular spectrum that the diamond is reflecting. While an integral part of AGS PGS construct, it is not the grading system per se. The system, through calculations by its ray tracer, assigns numerical deductions for deficits in brightness, contrast, leakage and dispersion. And since those deductions are cumulative, you can have small deficits in each characteristic that add up to a grade deduction.

One implication of this is that it is possible to see alot of red in an ASET and not get AGS 0. Conversely, it is possible to see a relatively large amount of green in ASET and still get AGS0 (depending on the shape).

Do you see what is wrong with this approach Bryan?
it would be far better if AGS would be open and transparent with its grades and let consumers (and cutters) know where any diamond scores on its RBC gradings - and use negative numbers where a stone outperforms their minimum standard.

Thenfor example, if any cut got -1 (a bonus) for fire, and +1 (penalty) for brightness, it could still be AGS0, but a different flavour - it could be Jazz, not Classical.
I bet consumers here would love that!

 

[Texas Leaguer]

You both have alluded to the actual AGSL grading metrics which I think is very important to keep in mind in this discussion; ASET is only the graphical representation of the angular spectrum that the diamond is reflecting. While an integral part of AGS PGS construct, it is not the grading system per se. The system, through calculations by its ray tracer, assigns numerical deductions for deficits in brightness, contrast, leakage and dispersion. And since those deductions are cumulative, you can have small deficits in each characteristic that add up to a grade deduction.

One implication of this is that it is possible to see alot of red in an ASET and not get AGS 0. Conversely, it is possible to see a relatively large amount of green in ASET and still get AGS0 (depending on the shape).

Do you see what is wrong with this approach Bryan?
it would be far better if AGS would be open and transparent with its grades and let consumers (and cutters) know where any diamond scores on its RBC gradings - and use negative numbers where a stone outperforms their minimum standard.

Thenfor example, if any cut got -1 (a bonus) for fire, and +1 (penalty) for brightness, it could still be AGS0, but a different flavour - it could be Jazz, not Classical.
I bet consumers here would love that!

I see your point Garry, but I would not necessarily say there is anything wrong with the approach. I think the premise is that there are a number of related but distinct aspects of light performance which must all be sufficiently present. The best cutting maximizes each of those elements in a balanced way for best performance over the widest range of real world conditions.

In terms of transparency, I don't think AGSL is hiding anything from anyone. The cutters know exactly how the system works and the specific penalties in the grading results they receive. They may not agree that a particular design should be penalized to the extent that it is (e.g. Yoram's contention that his red star cushion is getting some positive contribution from light coming from below the hemisphere).

I think too that it is possible to make a grading system too granular and therefore too difficult for the market to adopt. But I do get your point that because the AGS system is mathematical, there are many things they potentially could do in slicing and dicing the numbers in adaptive ways. And I'm sure you are right that many people here would be interested in further breakdown of their analysis.

 

[Rockdiamond]

My apologies for putting it badly Garry
I have a lot of faith that your work will bear even more fruit.


Any movement on AGSL cut grading for fancy shapes could be a very positive step.
It's just impossible to leave one's taste out if we're judging fancy shapes - therefore having a more broadly based approach will allow more consumers to benefit from AGSL methodology, which would clearly be a very good thing.
To y'all that are familiar with it- does spread come into play at all in AGSL cut grading of fancy shapes?

 

[Garry H (Cut Nut)]

I don't think you do get it Bryan.
Read my post again.
And I am not saying AGSL is doing anything underhanded.
But stopping a grading system at 0, or even 10, when there are potentially better and worse individual attributes they are attempting to quantify, is in my view, a mistake.
That they choose a mainstream 'balanced result" for "consumer protection" is also treating consumers like dummies.

Don't you think our consumers deserve better?

What grading system values on their PGS results would all the fancy and old cut variants they give AGS 0 grades for recieve on the RBC scale?
Is that not misleading if say an AGS0 cushion gets AGS 3 on the round scale?

 

[Garry H (Cut Nut)]

My apologies for putting it badly Garry
I have a lot of faith that your work will bear even more fruit.


Any movement on AGSL cut grading for fancy shapes could be a very positive step.
It's just impossible to leave one's taste out if we're judging fancy shapes - therefore having a more broadly based approach will allow more consumers to benefit from AGSL methodology, which would clearly be a very good thing.
To y'all that are familiar with it- does spread come into play at all in AGSL cut grading of fancy shapes?

Excellent question David.
AGSL does penalise for weight, but they do not share spread in any meangful way.
They could and they should in my opinion.
And they could and should with comparisons to RBC standard that they already have for rounds.
So an oval would often be +10% and a cushion might be -10%.
Dont you think consumers would like to know that? I call that being transparent.

The system they use is penalty based - its a rejection system.
It would not be hard for them to turn it something that had aspects of a selection system.

Edited later - Just searched a supplier with good info and found an oval with -7% of a modern Tolkowsky 57% table with no AGS spread penalty. It recieved AGS1 and has less than 0.7 DC light return - i.e. it has 30% less light return than a nice RBC.

 

[Rockdiamond]

Great concept Garry!
I absolutely agree that a fair percentage of consumers would be very interested in such a product.
In other words, if I understand correctly, a well cut FCD diamond, for example, might be 10, on a scale of 0 -10 as considered numerically against a round on a given set of parameters- including spread.
Different shapes would have different preferred ranges in the middle.
A 0 cut grade Princess Cut would be desirable to someone looking for max LP, while a 5 or 6 might be better for someone looking for spread.
Such a system might work for a broad range of stones even for :weird: shapes like Horsehead.

 

[Garry H (Cut Nut)]

Great concept Garry!
I absolutely agree that a fair percentage of consumers would be very interested in such a product.
In other words, if I understand correctly, a well cut FCD diamond, for example, might be 10, on a scale of 0 -10 as considered numerically against a round on a given set of parameters- including spread.
Different shapes would have different preferred ranges in the middle.
A 0 cut grade Princess Cut would be desirable to someone looking for max LP, while a 5 or 6 might be better for someone looking for spread.
Such a system might work for a broad range of stones even for :weird: shapes like Horsehead.

David that's close but not exactly as I see it.
A well cut FCD that was say Fancy Light, Fancy., FI or Vivid might be measured only by the absence of dark zones, and perhaps scintillation - the other colorless parameters may be less or even not be relevant.
A Deep or Dark may have some of the same desirable cut characteristics of a colorless stone.

But more importantly, all the information for a colorless stone might include light performance and spread data against the same weight (or maybe the same spread) Tolkowsky.
So for example in a princess cut (I used AGS PGS output - but just as an example).
Now from this you can see there is a need for heaps of salespersons upskilling. Otherwise Princess cut sales would plummet. But I believe all this info is what consumers have a right to.
We would need to generate an entire new language to communicate with consumers. And Joe Average may not care and might be just as happy shopping in a Maul Store. But his and Joesephen's total diamond spend might be 20% of what we can get Joe DiamondLover to buy after we teach him and her how to look at diamonds and appreciate them (aka wine appreciation courses and how they drastically increase spending on wine).

Can you imagine the world that the Cut Group envisages?
e.g. Diamond Design competitons, with prizes for the most firey, another for the brightest, and also for the most visible scintilation at 15 inches, and another at 1 metre. And Cutting Accuracy prizes. And of course, the grand prize for this years best Over-all Light Performance (judges, and popular choice awards).
The diamond industry is as boring as bat droppings and you'all reading this (especially you industry lurkers) can help \change this. Together we can turn this into an industry that you would actually want your children to work in.

 

[MelisendeDiamonds]

What grading system values on their PGS results would all the fancy and old cut variants they give AGS 0 grades for recieve on the RBC scale?
Is that not misleading if say an AGS0 cushion gets AGS 3 on the round scale?

As I understand it the cut group chose to use the Tolk round as a reference for spread and other properties and that is their choice.
AGSL recognizes that the theoretical maximum of each property is dependant upon physical facet structure.

The maximum a radiant cut design can get for brightness is not the same as a round brilliant. They recognize that and they don't penalize the radiant for its inherent limitations and lower order of symmetry.

Now I would agree the template and optimization for a new design is not transparent to the public due to its proprietary nature and that is a challenge to the understanding and acceptance of the AGSL cut grading system. But it isn't a consumer comparison system its a grading system used primarily these days for brand within a brand type of evaluations(within the same facet stucture) not comparing one brand to another or one shape to another.

 

[yssie]

What grading system values on their PGS results would all the fancy and old cut variants they give AGS 0 grades for recieve on the RBC scale?
Is that not misleading if say an AGS0 cushion gets AGS 3 on the round scale?

As I understand it the cut group chose to use the Tolk round as a reference for spread and other properties and that is their choice.
AGSL recognizes that the theoretical maximum of each property is dependant upon physical facet structure.

The maximum a radiant cut design can get for brightness is not the same as a round brilliant. They recognize that and they don't penalize the radiant for its inherent limitations and lower order of symmetry.

Now I would agree the template and optimization for a new design is not transparent to the public due to its proprietary nature and that is a challenge to the understanding and acceptance of the AGSL cut grading system. But it isn't a consumer comparison system its a grading system used primarily these days for brand within a brand type of evaluations(within the same facet strcuture) not comparing one brand to another or one shape to another.

Do you consider ASET to ideally function in the same capacity (permit meaningful brand-within-a-brand types of evaluations - between stones with the same facet structure)?

The ASET comparison you posted immediately prior is obviously of two stones with very different facet structures; I cannot determine whether you posted them together in suggestion of a meaningful use of the ASET scope or strictly to solicit argument from Mr. Grossbard.

I will say that your delivery of opinion - and delivery of response to professionals I greatly respect - rubs me the wrong way. It seems worth mentioning that your audience - and potential client-base - is far wider than the number of participants in this particular thread might suggest... I am but one of likely many educated consumers who are quietly following the discussion.

 

[RADIANTMAN]

In my view part of the problem here is that the words we use to describe characteristics of diamonds like "sparkle," "brightness" "fire" etc., are, first and foremost, English words with generic unscientific meanings to consumers. When we attempt to scientifically quantify these characteristics we first have to choose something that we can actually measure that we believe best correlates to what a consumer means when they use the word "brightness" then we have to decide things like what light conditions are most meaningful as we go about measuring it.

The only way that I can think of to test whether the measurement actually matches consumer perceptions of the meaning of the word would to conduct a serious consumer survey to see whether diamonds measured as being "brighter" are actually described as being "brighter" by consumers who are simply shown the diamonds and simply asked "which do you consider brighter?" Each adjective would have to be similarly tested and the test would have to be conducted in different lighting conditions to see if that changes the results.

Have such tests been conducted? If substantial enough testing has been done and the results conclusively agree with the measurement then both the use of the measurement and the use of the adjective to describe it seems to me to be appropriate. If not, then I think such testing needs to be done.

In addition, it is important to avoid creating the incorrect impression that "more" of a positive sounding characteristic such as "light return" is necessarily better and that "less" of a negative sounding characteristic such as "leakage" is necessarily worse. I think most people agree that diamonds need a proper balance of characteristics "More" may be "more" but depending on the balance of other characteristics "less" may actually be better.

A couple of weeks ago, I measured a radiant on my OGI firescope and it not only topped out on however they measure brilliance fire and scintillation and had 100% light return through the table. Unfortunately I did not save the data since I was going to re-cut the diamond anyway. I recut the diamond and after recutting (losing about 7% in weight) it still topped out in "fire" but bottomed out in brilliance and scintilation. Light return dropped to 67%. I actually wasn't particularly surprised by this result since well cut radiants seem to consistently receive high "fire" scores on the firescope and low brilliance and scintilation scores and have light return around 60-70%

In my opinion, obviously sincere since I owned it and re-cut it) the diamond before re-cutting was virtually unsaleable because of its appearance. The re-cut diamond would be considered, by everyone I know in the trade, to be a beautiful cut. Now I don't know what OGI is measuring and calling "brilliance" "fire" or "scintillation" or how they measure "light return" or how they are measuring it (I'm sure some of you do) but except for "fire" it does not appear to me that more is better it appears to me that more is often worse.

Finally, I completely agree with Garry that it would be useful to measure spread on all diamonds, including RBC's and score them using a well cut Tolk RBC as the standard because, all else being equal, looking bigger rather than smaller is a positive for any diamond.

I do not agree that a Tolk RBC is an appropriate standard against which to evaluate other characteristics of fancy shapes that are not cut with the goal of looking like square or rectangular or oval or pearshaped RBC's. It is far more useful to develop a system that helps consumers understand how an oval or emerald cut or radiant compares to a standard developed for that cut rather than to a standard developed for rounds. And it makes sense to compare each characteristic to an optimum in which deductions are made for being too high as well as to low or having too much or too little of one characteristic relative to another.


"

 

[Texas Leaguer]

This specific design was analyzed by AGSL on its 3D file, it got deductions as you estimated very well both for brightness 0.60 & leakage 0.31.

Maybe if we could have the algorithm numerical value listed on the grading reports we could have a better chance utilizing the AGSL grading system for other cuts rather than just triple 0's.

I think consumers will be better informed if we can show them how the grade was set.

Yes more information available on the grading report would be beneficial as long as it can't be used to game the system.
I don't use AGS-PGS so I don't know if the LP breakdown is given on the software report is it?

As I assumed before the leakage part is not relevant for this design getting the top grade, the loss of brightness already puts it into AGS 1 territory so whether they give it a break on leakage due to "low angle leakage" would not matter for grading.

You both have alluded to the actual AGSL grading metrics which I think is very important to keep in mind in this discussion; ASET is only the graphical representation of the angular spectrum that the diamond is reflecting. While an integral part of AGS PGS construct, it is not the grading system per se. The system, through calculations by its ray tracer, assigns numerical deductions for deficits in brightness, contrast, leakage and dispersion. And since those deductions are cumulative, you can have small deficits in each characteristic that add up to a grade deduction.

Yes correct, and properties with tilt are also considered in AGS-PGS while in ASET they are not. Also it isn't red or green that is given one value for brightness, how close the region is to the 45 - 75 is given a weighted deduction as well.

One implication of this is that it is possible to see alot of red in an ASET and not get AGS 0. Conversely, it is possible to see a relatively large amount of green in ASET and still get AGS0 (depending on the shape).

Both have lots of red, both are bright stones along the crown but very different under the table. One of these gets AGS 0 the other does not and there is a definite brilliance difference between the two yet they have the same physical facet structure.



It isn't about a lot, its about enough and about getting to the "optimal" amount of brightness possible out of a particular physical facet arrangement. For some brands AGSL isn't strict enough, for others too strict and there will always be those who complain on both sides.

Just a point of order MD- the first quote you attributed to me above was actually made by Diagem. I do not necessarily disagree with it, but I would not have said it simply because I personally do not feel qualified to say what would be or would not be helpful with respect to fancy shapes. It does seem logical though and also seems in line with the kind of additional information Garry is suggesting that the Cut Group envisions providing.

How practical it would be is an open question. I'm sure AGSL has to make difficult judgments as to what information to put out. I know they have done some trial programs with additional metrics such as the Scintillation report. But I also know they have some customers who feel they already have too many reports and that it may be confusing to the market. It is a balance they must try to achieve. The good thing is that the nature of the system makes it capable of evolving.

 

[Texas Leaguer]

What grading system values on their PGS results would all the fancy and old cut variants they give AGS 0 grades for recieve on the RBC scale?
Is that not misleading if say an AGS0 cushion gets AGS 3 on the round scale?

As I understand it the cut group chose to use the Tolk round as a reference for spread and other properties and that is their choice.
AGSL recognizes that the theoretical maximum of each property is dependant upon physical facet structure.

The maximum a radiant cut design can get for brightness is not the same as a round brilliant. They recognize that and they don't penalize the radiant for its inherent limitations and lower order of symmetry.

Now I would agree the template and optimization for a new design is not transparent to the public due to its proprietary nature and that is a challenge to the understanding and acceptance of the AGSL cut grading system. But it isn't a consumer comparison system its a grading system used primarily these days for brand within a brand type of evaluations(within the same facet stucture) not comparing one brand to another or one shape to another.

I generally agree with this characterization of the AGSL approach to fancy shapes. At least that is also my general understanding.

I think there is an unfortunate aspect to the way the market has embraced AGSL grading- i.e. only the Zero is highly valued. Some of the debate here would probably not be as heated if you had a situation where people appreciated AGS 1 and 2 grades as being high end. But there seems to be a sense of pass/fail with regards to Zero. That leads to resentment against the system, even though it is really a continuum of 10 possible grades. So the problem may lie more in market perception of the system than with the system itself.

 

[Serg]

What grading system values on their PGS results would all the fancy and old cut variants they give AGS 0 grades for recieve on the RBC scale?
Is that not misleading if say an AGS0 cushion gets AGS 3 on the round scale?

As I understand it the cut group chose to use the Tolk round as a reference for spread and other properties and that is their choice.
AGSL recognizes that the theoretical maximum of each property is dependant upon physical facet structure.

The maximum a radiant cut design can get for brightness is not the same as a round brilliant. They recognize that and they don't penalize the radiant for its inherent limitations and lower order of symmetry.

Now I would agree the template and optimization for a new design is not transparent to the public due to its proprietary nature and that is a challenge to the understanding and acceptance of the AGSL cut grading system. But it isn't a consumer comparison system its a grading system used primarily these days for brand within a brand type of evaluations(within the same facet stucture) not comparing one brand to another or one shape to another.

I generally agree with this characterization of the AGSL approach to fancy shapes. At least that is also my general understanding.

I think there is an unfortunate aspect to the way the market has embraced AGSL grading- i.e. only the Zero is highly valued. Some of the debate here would probably not be as heated if you had a situation where people appreciated AGS 1 and 2 grades as being high end. But there seems to be a sense of pass/fail with regards to Zero. That leads to resentment against the system, even though it is really a continuum of 10 possible grades. So the problem may lie more in market perception of the system than with the system itself.

Score system creates better opportunities for marketing than penalty system.
Too strict penalty system would penalises any improvements, innovations and finally destroys itself.

 

[MelisendeDiamonds]

What grading system values on their PGS results would all the fancy and old cut variants they give AGS 0 grades for recieve on the RBC scale?
Is that not misleading if say an AGS0 cushion gets AGS 3 on the round scale?

As I understand it the cut group chose to use the Tolk round as a reference for spread and other properties and that is their choice.
AGSL recognizes that the theoretical maximum of each property is dependant upon physical facet structure.

The maximum a radiant cut design can get for brightness is not the same as a round brilliant. They recognize that and they don't penalize the radiant for its inherent limitations and lower order of symmetry.

Now I would agree the template and optimization for a new design is not transparent to the public due to its proprietary nature and that is a challenge to the understanding and acceptance of the AGSL cut grading system. But it isn't a consumer comparison system its a grading system used primarily these days for brand within a brand type of evaluations(within the same facet stucture) not comparing one brand to another or one shape to another.

I generally agree with this characterization of the AGSL approach to fancy shapes. At least that is also my general understanding.

I think there is an unfortunate aspect to the way the market has embraced AGSL grading- i.e. only the Zero is highly valued. Some of the debate here would probably not be as heated if you had a situation where people appreciated AGS 1 and 2 grades as being high end. But there seems to be a sense of pass/fail with regards to Zero. That leads to resentment against the system, even though it is really a continuum of 10 possible grades. So the problem may lie more in market perception of the system than with the system itself.

Some vendors get the diamond graded by GIA for their report and then publish the AGS-PGS report to show the LP grade. I bet that is not how AGSL would have preferred things to go as they won't get the business that way but that is how it may be used in cases where Symmetry, Polish or one of the proportion factors are not up to AGSL's top grade.

 

[Texas Leaguer]

What grading system values on their PGS results would all the fancy and old cut variants they give AGS 0 grades for recieve on the RBC scale?
Is that not misleading if say an AGS0 cushion gets AGS 3 on the round scale?

As I understand it the cut group chose to use the Tolk round as a reference for spread and other properties and that is their choice.
AGSL recognizes that the theoretical maximum of each property is dependant upon physical facet structure.

The maximum a radiant cut design can get for brightness is not the same as a round brilliant. They recognize that and they don't penalize the radiant for its inherent limitations and lower order of symmetry.

Now I would agree the template and optimization for a new design is not transparent to the public due to its proprietary nature and that is a challenge to the understanding and acceptance of the AGSL cut grading system. But it isn't a consumer comparison system its a grading system used primarily these days for brand within a brand type of evaluations(within the same facet stucture) not comparing one brand to another or one shape to another.

I generally agree with this characterization of the AGSL approach to fancy shapes. At least that is also my general understanding.

I think there is an unfortunate aspect to the way the market has embraced AGSL grading- i.e. only the Zero is highly valued. Some of the debate here would probably not be as heated if you had a situation where people appreciated AGS 1 and 2 grades as being high end. But there seems to be a sense of pass/fail with regards to Zero. That leads to resentment against the system, even though it is really a continuum of 10 possible grades. So the problem may lie more in market perception of the system than with the system itself.

Score system creates better opportunities for marketing than penalty system.
Too strict penalty system would penalises any improvements, innovations and finally destroys itself.

Serg,
You mentioned the wine tasting analogy earlier. Try this; think of a stereo equalizer. Some folks like music with a driving base - others the crispness associated with high levels of mid range and treble. Or you might like a straight line where all frequencies have equal prominence. Certain genres of music (like facet arrangements) might be best enjoyed with specific equalizer settings (brightness, fire, contrast). Digital equalizers have presets for rock, jazz, sports arena, etc. No pattern of relative values is necessarily good or bad. It depends on the type of music you like to listen to and how a particular combination of levels sounds to your ear.

The challenge is understanding the metrics and learning what the different levels mean for your particular listening tastes.

 

[Garry H (Cut Nut)]

What grading system values on their PGS results would all the fancy and old cut variants they give AGS 0 grades for recieve on the RBC scale?
Is that not misleading if say an AGS0 cushion gets AGS 3 on the round scale?

As I understand it the cut group chose to use the Tolk round as a reference for spread and other properties and that is their choice.
AGSL recognizes that the theoretical maximum of each property is dependant upon physical facet structure.

The maximum a radiant cut design can get for brightness is not the same as a round brilliant. They recognize that and they don't penalize the radiant for its inherent limitations and lower order of symmetry.

Now I would agree the template and optimization for a new design is not transparent to the public due to its proprietary nature and that is a challenge to the understanding and acceptance of the AGSL cut grading system. But it isn't a consumer comparison system its a grading system used primarily these days for brand within a brand type of evaluations(within the same facet stucture) not comparing one brand to another or one shape to another.

I generally agree with this characterization of the AGSL approach to fancy shapes. At least that is also my general understanding.

I think there is an unfortunate aspect to the way the market has embraced AGSL grading- i.e. only the Zero is highly valued. Some of the debate here would probably not be as heated if you had a situation where people appreciated AGS 1 and 2 grades as being high end. But there seems to be a sense of pass/fail with regards to Zero. That leads to resentment against the system, even though it is really a continuum of 10 possible grades. So the problem may lie more in market perception of the system than with the system itself.

Score system creates better opportunities for marketing than penalty system.
Too strict penalty system would penalises any improvements, innovations and finally destroys itself.

Serg,
You mentioned the wine tasting analogy earlier. Try this; think of a stereo equalizer. Some folks like music with a driving base - others the crispness associated with high levels of mid range and treble. Or you might like a straight line where all frequencies have equal prominence. Certain genres of music (like facet arrangements) might be best enjoyed with specific equalizer settings (brightness, fire, contrast). Digital equalizers have presets for rock, jazz, sports arena, etc. No pattern of relative values is necessarily good or bad. It depends on the type of music you like to listen to and how a particular combination of levels sounds to your ear.

The key is understanding the metrics and learning what the different levels mean for your particular listening tastes.

Bryan the only way consumers can control the music from their diamonds is to have a scoring system. They can turn up the aspects they like. A penalty system that never shows you the maximum capacity of base could kill some genres like hard rock.

 

[MelisendeDiamonds]

In my view part of the problem here is that the words we use to describe characteristics of diamonds like "sparkle," "brightness" "fire" etc., are, first and foremost, English words with generic unscientific meanings to consumers.

Would you please explain what your father meant by the word Brilliance in his 1982 patent application. It would seem that in a patent it should be quite clear what the word means to him. Maybe that would shed some light on what "Unparalleled Brilliance" means.

 

[Karl_K]

Bryan the only way consumers can control the music from their diamonds is to have a scoring system. They can turn up the aspects they like. A penalty system that never shows you the maximum capacity of base could kill some genres like hard rock.

But a system with an RB as the gold standard is also a broken system in the same way that the AGSL system is broken.
Designing a step cut to perform like a round is a step in the wrong direction for step cuts.
There are basic incompatibilities between a system that grades like an RB and one that grades step cuts.
You end up with a system like the b-scope that only rewards highly directional diamonds that return high angle lighting if you use an RB as the gold standard.
Step cuts do not function that way. The system is already in trouble when they are dismissed out of hand as Serg did.

 

[Karl_K]

In my view part of the problem here is that the words we use to describe characteristics of diamonds like "sparkle," "brightness" "fire" etc., are, first and foremost, English words with generic unscientific meanings to consumers.

Would you please explain what your father meant by the word Brilliance in his 1982 patent application. It would seem that in a patent it should be quite clear what the word means to him. Maybe that would shed some light on what "Unparalleled Brilliance" means.

Knock it off!
Attacking someones product is out of bounds and attacking someones Dad is just down right rude wrong and uncalled for!
I am reporting my post as soon as I post it, but frankly I have had it.

 

[Texas Leaguer]

What grading system values on their PGS results would all the fancy and old cut variants they give AGS 0 grades for recieve on the RBC scale?
Is that not misleading if say an AGS0 cushion gets AGS 3 on the round scale?

As I understand it the cut group chose to use the Tolk round as a reference for spread and other properties and that is their choice.
AGSL recognizes that the theoretical maximum of each property is dependant upon physical facet structure.

The maximum a radiant cut design can get for brightness is not the same as a round brilliant. They recognize that and they don't penalize the radiant for its inherent limitations and lower order of symmetry.

Now I would agree the template and optimization for a new design is not transparent to the public due to its proprietary nature and that is a challenge to the understanding and acceptance of the AGSL cut grading system. But it isn't a consumer comparison system its a grading system used primarily these days for brand within a brand type of evaluations(within the same facet stucture) not comparing one brand to another or one shape to another.

I generally agree with this characterization of the AGSL approach to fancy shapes. At least that is also my general understanding.

I think there is an unfortunate aspect to the way the market has embraced AGSL grading- i.e. only the Zero is highly valued. Some of the debate here would probably not be as heated if you had a situation where people appreciated AGS 1 and 2 grades as being high end. But there seems to be a sense of pass/fail with regards to Zero. That leads to resentment against the system, even though it is really a continuum of 10 possible grades. So the problem may lie more in market perception of the system than with the system itself.

Score system creates better opportunities for marketing than penalty system.
Too strict penalty system would penalises any improvements, innovations and finally destroys itself.

Serg,
You mentioned the wine tasting analogy earlier. Try this; think of a stereo equalizer. Some folks like music with a driving base - others the crispness associated with high levels of mid range and treble. Or you might like a straight line where all frequencies have equal prominence. Certain genres of music (like facet arrangements) might be best enjoyed with specific equalizer settings (brightness, fire, contrast). Digital equalizers have presets for rock, jazz, sports arena, etc. No pattern of relative values is necessarily good or bad. It depends on the type of music you like to listen to and how a particular combination of levels sounds to your ear.

The key is understanding the metrics and learning what the different levels mean for your particular listening tastes.

Bryan the only way consumers can control the music from their diamonds is to have a scoring system. They can turn up the aspects they like. A penalty system that never shows you the maximum capacity of base could kill some genres like hard rock.

I hear ya Garry. That's why I thought you would like the equalizer analogy. There are no real limits, nor any judgment about what is best. You can turn the base all the way up and everything else down if you want. But because the end result is to a large extent interrelated, there will turn out to be combinations that are more popular than others, some that a majority of folks like, and some combos that very few people like. You know, like on a zero to ten scale. Just kidding!!!

 

[Garry H (Cut Nut)]

What grading system values on their PGS results would all the fancy and old cut variants they give AGS 0 grades for recieve on the RBC scale?
Is that not misleading if say an AGS0 cushion gets AGS 3 on the round scale?

As I understand it the cut group chose to use the Tolk round as a reference for spread and other properties and that is their choice.
AGSL recognizes that the theoretical maximum of each property is dependant upon physical facet structure.

The maximum a radiant cut design can get for brightness is not the same as a round brilliant. They recognize that and they don't penalize the radiant for its inherent limitations and lower order of symmetry.

Now I would agree the template and optimization for a new design is not transparent to the public due to its proprietary nature and that is a challenge to the understanding and acceptance of the AGSL cut grading system. But it isn't a consumer comparison system its a grading system used primarily these days for brand within a brand type of evaluations(within the same facet stucture) not comparing one brand to another or one shape to another.

I generally agree with this characterization of the AGSL approach to fancy shapes. At least that is also my general understanding.

I think there is an unfortunate aspect to the way the market has embraced AGSL grading- i.e. only the Zero is highly valued. Some of the debate here would probably not be as heated if you had a situation where people appreciated AGS 1 and 2 grades as being high end. But there seems to be a sense of pass/fail with regards to Zero. That leads to resentment against the system, even though it is really a continuum of 10 possible grades. So the problem may lie more in market perception of the system than with the system itself.

Score system creates better opportunities for marketing than penalty system.
Too strict penalty system would penalises any improvements, innovations and finally destroys itself.

Serg,
You mentioned the wine tasting analogy earlier. Try this; think of a stereo equalizer. Some folks like music with a driving base - others the crispness associated with high levels of mid range and treble. Or you might like a straight line where all frequencies have equal prominence. Certain genres of music (like facet arrangements) might be best enjoyed with specific equalizer settings (brightness, fire, contrast). Digital equalizers have presets for rock, jazz, sports arena, etc. No pattern of relative values is necessarily good or bad. It depends on the type of music you like to listen to and how a particular combination of levels sounds to your ear.

The key is understanding the metrics and learning what the different levels mean for your particular listening tastes.

Bryan the only way consumers can control the music from their diamonds is to have a scoring system. They can turn up the aspects they like. A penalty system that never shows you the maximum capacity of base could kill some genres like hard rock.

I hear ya Garry. That's why I thought you would like the equalizer analogy. There are no real limits, nor any judgment about what is best. You can turn the base all the way up and everything else down if you want. But because the end result is to a large extent interrelated, there will turn out to be combinations that are more popular than others, some that a majority of folks like, and some combos that very few people like. You know, like on a zero to ten scale. Just kidding!!!

hahahaha - like the cheap boom boxes that have "concert hall" "disco" etc settings Bryan
Yes, we are on the same wavelength (pun)

 

[Texas Leaguer]

In my view part of the problem here is that the words we use to describe characteristics of diamonds like "sparkle," "brightness" "fire" etc., are, first and foremost, English words with generic unscientific meanings to consumers.

Would you please explain what your father meant by the word Brilliance in his 1982 patent application. It would seem that in a patent it should be quite clear what the word means to him. Maybe that would shed some light on what "Unparalleled Brilliance" means.

Knock it off!
Attacking someones product is out of bounds and attacking someones Dad is just down right rude wrong and uncalled for!
I am reporting my post as soon as I post it, but frankly I have had it.

Karl,
Don't call the cops yet. Stan made a very thoughtful post with alot of merit. However, he called into question some rather intuitive concepts and argued the need for better definitions before measurements can be valid. He apparently uses some of these definitions in his own marketing (as we all do), so I think it is fair to ask him his interpretations.

From what we are learning about neuroscience, there may indeed be a need to go back to the basics to define things like brightness. Ouch.

 

[MelisendeDiamonds]

In my view part of the problem here is that the words we use to describe characteristics of diamonds like "sparkle," "brightness" "fire" etc., are, first and foremost, English words with generic unscientific meanings to consumers.

Would you please explain what your father meant by the word Brilliance in his 1982 patent application. It would seem that in a patent it should be quite clear what the word means to him. Maybe that would shed some light on what "Unparalleled Brilliance" means.

Knock it off!
Attacking someones product is out of bounds and attacking someones Dad is just down right rude wrong and uncalled for!
I am reporting my post as soon as I post it, but frankly I have had it.

edit: Self Reported by Karl Already so I will not dwell on it.

You have read so many things into my question that I don't feel are even there.

I will reiterate again Brian's correct interpretation of my post above, my question was about Henry and Stan's definition of brilliance. The answer to my question will hopefully clarify the marketing statement I posted in the images above.

Otherwise with no answer to the definition of brilliance as John Pollard stated his prophecy will hold true.

I tend to abandon threads where people are using similar vocabulary but seem to insist on playing different games: If one person applies NFL rules and another applies CFL rules the fundamental length of the field is a contradiction. So, while discussion using football terms and ideas is happening, no consensus can happen because the playing fields are ultimately different. In such threads heads still pound bricks over fundamentals many pages later.

 

[RADIANTMAN]

Bryan perhaps I wasn't clear enough. The point of my post was that it doesn't matter what a word like brilliance means to me or you or to the AGSL or to the cut group. What matters is what it means generically to people generally and whether whatever it is that we are objectively measuring matches people's visual understanding of the label we are applying to the measurement. If it doesn't we need to measure it differently or describe the characteristic we are measuring differently. I asked whether consumer testing had been done to confirm whether the measurement matched the public's intuitive understanding of the label being used to describe it. My personal opinion matters not at all nor does it matter what my father meant in his patent application or what the phrase on my website means to me. Consumers who see our diamonds and disagree with me and consider cut cornered princesses brighter will buy those instead but they are unlikely to disbelieve their eyes because of something I have said or frankly that the AGSL or the cut group says. They will trust their eyes and any standard that doesn't match what people see will not ultimately be accepted as credible. We need to learn to measure what people like not try to use science to convince them to like something else. Any attempt to develop a standard that does that simply will not succeed. Even if all the experts on here were to agree (which I doubt is the case) it wouldn't matter. Words need to be used in the manner people not in the trade understand them and any grading standard that doesn't do that will not well serve it's intended purpose.

I am not saying that this is the case with the cut group's definitions only that without testing we don't know.

 

[Rockdiamond]

In my view part of the problem here is that the words we use to describe characteristics of diamonds like "sparkle," "brightness" "fire" etc., are, first and foremost, English words with generic unscientific meanings to consumers.

Would you please explain what your father meant by the word Brilliance in his 1982 patent application. It would seem that in a patent it should be quite clear what the word means to him. Maybe that would shed some light on what "Unparalleled Brilliance" means.

Knock it off!
Attacking someones product is out of bounds and attacking someones Dad is just down right rude wrong and uncalled for!
I am reporting my post as soon as I post it, but frankly I have had it.

Karl,
Don't call the cops yet. Stan made a very thoughtful post with alot of merit. However, he called into question some rather intuitive concepts and argued the need for better definitions before measurements can be valid. He apparently uses some of these definitions in his own marketing (as we all do), so I think it is fair to ask him his interpretations.

From what we are learning about neuroscience, there may indeed be a need to go back to the basics to define things like brightness. Ouch.

+1 Karl.
Bryan,
I think Stan was very clear in his answer.
Every one of us could comb through the other's website and find things we'd say differently- or a principle we may not subscribe to.
Unless it's done with the intent of helping, it's dirty pool IMO.
If MD has a question, they can ask respectfully- well apparently they can't, but they should.
As far as your last point, I've been hammering that for years.
Ouch should refer to a lopsided discussion based on terms that are touted as "scientific" that are subjective interpretations of visual phenomena.

ETA- Stan and I were posting at the same time.

 

[Garry H (Cut Nut)]

Bryan perhaps I wasn't clear enough. The point of my post was that it doesn't matter what a word like brilliance means to me or you or to the AGSL or to the cut group. What matters is what it means generically to people generally and whether whatever it is that we are objectively measuring matches people's visual understanding of the label we are applying to the measurement. If it doesn't we need to measure it differently or describe the characteristic we are measuring differently. I asked whether consumer testing had been done to confirm whether the measurement matched the public's intuitive understanding of the label being used to describe it. My personal opinion matters not at all nor does it matter what my father meant in his patent application or what the phrase on my website means to me. Consumers who see our diamonds and disagree with me and consider cut cornered princesses brighter will buy those instead but they are unlikely to disbelieve their eyes because of something I have said or frankly that the AGSL or the cut group says. They will trust their eyes and any standard that doesn't match what people see will not ultimately be accepted as credible. We need to learn to measure what people like not try to use science to convince them to like something else. Any attempt to develop a standard that does that simply will not succeed. Even if all the experts on here were to agree (which I doubt is the case) it wouldn't matter. Words need to be used in the manner people not in the trade understand them and any grading standard that doesn't do that will not well serve it's intended purpose.

I am not saying that this is the case with the cut group's definitions only that without testing we don't know.

Stan the real testing that we propose is crowd sourcing. TheCut Group can not over emphasize that we will use science when science works, and expert assessment when the science can not (e.g. there are many features of optical illusions that are not fully understood by vision scientists).

For the record, and its a lot to read - here is Box A from our Australian Gemmologist 40 page article (that was shrunk to 6 in Rap mag).
The point being that there are so many definitions and they vary as much from country to country as they do from person to person and over time:
Box A Definitions of "Brilliance"

From Tolkowsky's "Diamond Design", 1919:

The brilliancy or, as it is sometimes termed, the "fire" or the "life" of a gem thus depends entirely upon the play of light in the gem, upon the path of rays of light in the gem. If a gem is so cut or designed that every ray of light passing into it follows the best path possible for producing pleasing effects upon the eye, then the gem is perfectly cut.

Diamonds, E. Bruton (197:

Eric Bruton F.G.A. gives in his book "Diamonds" a definition of brilliance that can be collected from a number of passages of his book: "This quality of returning the maximum amount of light from the stone to the eye – from the surface lustre and from internal reflection – is known as "life". The fire of a gem is the display of spectrum colors (and scintillation) caused by its refracting white light before returned to the eye". "Brilliance has never been exactly defined. As it is used in a general way, it should cover all the visual properties which have been concentrated, in the two last paragraphs, into the terms "life" and "fire". .....The brilliance of a stone depends upon the optimum combination of its life and fire. If the two qualities could be quantified, brilliance would be at maximum when life X fire was at a maximum".

GIA Diamond Dictionary, 3rd edition:

Intensity of the internal and external reflections of white light from the crown of a polished diamond or other gemstone. Hardness, refractive index, reflectivity, polish, lustre, and proportions all affect a gemstone's brilliance.

Diamond Grading ABC by V. Pagel-Theisen, 11th edition:

External brilliance – lustre, produced by reflection of light on the surface of the facets; Internal brilliance – refraction and total reflection of light on the pavilion facets; Dispersive brilliance – splitting of scattering of light into its spectral colors = the dispersion which evokes the "fire" or "life" in a brilliant; scintillation brilliance – the "sparkle" of the stone when moved, caused by light reflections of the light source.

Dodson's definition (197:

A measure of the light that, entering the crown of the stone, is scattered out of the crown facets.

"Professional Jeweler" (July 199 Light Return/Brilliance :

The amount of light returned to the eye, or brilliance, depends on how well the diamond in question reflects and refracts light. This includes dispersed wavelengths, which are reflected from the internal surfaces of a diamond and returned to the eye.

GIA (Hemphil et al., 199:

White light returned through the crown (excluding glare – light directly reflected from the top surface).

Garry Holloway: http://www.diamond-cut.com.au/09_brill.htm

Brilliance is the human perception of diamond brightness. It is the most important feature of a beautiful diamond.

Brilliance is not simply light return; it involves complex issues that include scintillation or contrast with the added variable of human perception. However a diamond with poor light return cannot display optimal beauty.

Fire is the term used to describe flashes of color resulting from spectral separation or dispersion of white light into rainbow flashes.

Authors from AGS Lab (Sassian et al., 2007)

Gem Brilliance – Gemstone brilliance refers to the ability of a stone to appear illuminated to an observer. For this to occur light must be directed from the virtual facets to the observer’s eyes. .... For understanding the illumination appearance of a gem it is useful to think of a gem’s facets and their optical projections, the virtual facets, as a collection of tiny prisms that direct light to an observer’s eyes. Brilliance [can be defined] as the percentage by area of such tiny prisms that can direct light to the observer’s eyes. This definition is simple and does not intend to account for obliquity factors that could be included to account for differences in the relative position of facets or illumination conditions.

Gem Contrast – The high angular range ... indicates the zones in a stone’s crown that are not
illuminated due to the obscuration of the observer’s head. This obscuration produces what is known in the trade as gem contrast. In proper amount and distribution, contrast creates structured lighting that enhances brilliance, fire, and scintillation. Contrast can be a detrimental effect if it is significantly localized. Too little contrast results in a stone’s appearance lacking variety under broad diffused illumination. Too much contrast results in a stone that lacks brilliance. The combination of positive contrast characteristics and brilliance properties in a gemstone is known as contrast brilliance.
When a gemstone is in movement the contrast pattern changes in form. This effect is called dynamic contrast and adds substantial appeal to the appearance of a stone.

Gem Fire – The phenomenon of fire is one of the most appealing effects in transparent gemstones. Under favorable conditions fire makes individual facets appear fully colored with the rainbow hues. Fire inherently occurs due to the light dispersion upon refraction as light enters and exits a stone.
Three factors determine the amount of fire perceived from a facet, namely, the angular dispersion of light upon refraction from the gemstone, the angular subtend of the source, and the angular subtend of the eye’s pupil in relation to the facet. To best observe fire it is required to have a localized source of light so that its angular subtend is much smaller than the angular dispersion produced by the gem facet, essentially a point source. As different colored rays arrive to the eye from a facet, some of them enter the eye’s pupil and others are blocked producing a colored appearance of the facet. In this process the boundary of the eye’s pupil plays a critical role in obstructing portions of the spectrum to achieve the colored facet appearance.

Gem Scintillation – In the presence of brilliance and fire the most appealing effect is gem scintillation. Thus there are two major scintillation effects, fire and flash scintillation. To observe them it is required that the stone, the observer, or the illumination conditions be in movement. Typically the observer tilts the stone back and forth to observe scintillation and naturally optimizes for the direction that maximizes scintillation. Without brilliance... there cannot be fire since no light can be brought to the observer’s eyes. Without fire there cannot be fire scintillation as defined by the change of fire pattern. Flash scintillation can occur without fire scintillation and it is due to light sources not small enough in angular subtend (point source) to produce fire, or to the inability of a stone to sufficiently disperse light for a given position of the observer. Diffuse white illumination will wash out both scintillation effects. Sources that subtend a small angle will contribute more to produce a flash effect, the rapid turn on and off of the light from a given facet, than sources that subtend larger angles. Thus fire scintillation is more vivid than flash scintillation. The amount of gem scintillation perceived is linked to the brilliance and fire of a stone. However, scintillation strongly depends on the change of illumination conditions. This change is primarily produced on purpose by the movement of the stone as it is admired.

Pricescope Internet resource (2010) https://www.pricescope.com/wiki/diamonds/diamond-brilliance-fire-scintillation/
Brilliance is an essential attribute of a beautiful diamond and has 2 components: brightness and contrast. Bright diamonds return lots of light from the surroundings back to a 'face up' observer. If light from above leaks out the back of a diamond, naturally it has less brightness. But light that enters and leaves in the face up direction is wasted because your head blocks lights from that direction. Diamonds that are too deep or very shallow do this – they have areas that act like a mirror back to the viewer; they return less light and so they have less brightness.

But to be brilliant, a diamond needs more than just brightness from light return. Consider the contrast of a chessboard, although it has only half the light return of a sheet of white paper, it appears brighter, especially when it is moved because it 'scintillates'.

 

[Rockdiamond]

How about a totally different possibility- that struck me just now.
I have mentioned that I think it's important to acknowledge that the most artistic, and creative designs and implementation of diamond cuts come from people that hold opinions strongly.
If we sat down at a table with the most creative minds alive in the diamond business today, there'd be many shared ideas- and there would be broad disagreement about a lot of things too.

Point is, the cut group is following a path they believe to be the best.
Whatever crowd source used will be influenced by the test, and many other factors.
I trust the cut group knows what they are doing. They can help a lot of cutters, without a doubt.
I guarantee you people like Yoram and Stan will take other paths. Thank goodness for diversity.
Maybe, we need to find a way to judge a Porsche 911, against a Bentley against a Hummer.

There's never going to be one right answer.
Garry- those textbook style definitions are interpretations ( and boring)....well, here's the bible

From Tolkowsky's "Diamond Design", 1919:

The brilliancy or, as it is sometimes termed, the "fire" or the "life" of a gem thus depends entirely upon the play of light in the gem, upon the path of rays of light in the gem. If a gem is so cut or designed that every ray of light passing into it follows the best path possible for producing pleasing effects upon the eye, then the gem is perfectly cut.

That's it.
Pleasing effects on the eye.
You and I may not agree which is the most pleasing but plenty of people agree with me, and plenty agree with you.
There's a range of pleasing effects.

 

[Garry H (Cut Nut)]

.

I think there is an unfortunate aspect to the way the market has embraced AGSL grading- i.e. only the Zero is highly valued. Some of the debate here would probably not be as heated if you had a situation where people appreciated AGS 1 and 2 grades as being high end. But there seems to be a sense of pass/fail with regards to Zero. That leads to resentment against the system, even though it is really a continuum of 10 possible grades. So the problem may lie more in market perception of the system than with the system itself.

Bryan I think that is just a commercial reality. GIA XXX is probably going to fetch more $$$ than AGS 1-10.
So AGSL have painted themselves into an exclusive corner. Its nothing really about resentment.

I am glad that they relaxed the Ideal Sym and Polish though - back to XX. I wonder how many people in the trade who are or could be their clients even know about that though?