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AGS introduces cut grading on DQR reports
- Thread starter Garry H (Cut Nut)
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Gentlemen,
Let us look at this matter from a proper perspective. Even though they are sister-organisations, the AGS-Lab and GIA-GTL are direct competitors in the business of grading diamonds. In a way, it might be considered unfortunate that the lab-business is a commercial business, and not a government-regulated one, but we have to deal with realities here.
Before 2006 AGS had two main documents, the AGS DQD with Cut-grade - which GIA did not have, and the AGS DQR with the same set-up as a GIA-report. What is important to remember is that neither the DQR nor the GIA-report had a cut grade, they judged only polish and symmetry.
In 2005 the AGS DQD went up one level, by going from a 2D proportions-based Cut-grade to a 3D light performance-based grade. I trust that everyone sees this as an improvement for the consumer, especially since I remember many of us pointing out the errors in the proportions-based system at that time. The DQR remained as it was.
In January 2006, GIA started its own Cut-grade, based upon proportions. Everybody here agrees that it is less strict than the AGS-system, and there is also serious argument about its basics with proportion-grading only, and flawed research.
What you are failing to see is since that time the AGS-DQR has no longer been a direct potential substitute for this new GIA-report. Thus, from a competitive point-of-view, it is logical that AGS was going to re-think the DQR and introduce a new system for it which, as-before, is less stringent than the DQD, but better than the GIA-report.
Well, here we are, this is the new DQR. Just like GIA, it is proportion-grading again. Polish and Symmetry are used in the same way as with GIA. But unlike GIA, these proportions are based upon the 3-dimensional research that is the basis of their superior DQD. Whichever way you turn it, this is a product positioned directly opposite the GIA-report, only stricter in some areas.
The introduction of this product is entirely logical from a competitive point of view, and one should not be surprised by it.
As I am not going to use this new DQR, I see no reason to defend its pros nor cons. But there is no ground to misuse this introduction to create a storm of unnecessary unrest and misinformation.
Live long
Let us look at this matter from a proper perspective. Even though they are sister-organisations, the AGS-Lab and GIA-GTL are direct competitors in the business of grading diamonds. In a way, it might be considered unfortunate that the lab-business is a commercial business, and not a government-regulated one, but we have to deal with realities here.
Before 2006 AGS had two main documents, the AGS DQD with Cut-grade - which GIA did not have, and the AGS DQR with the same set-up as a GIA-report. What is important to remember is that neither the DQR nor the GIA-report had a cut grade, they judged only polish and symmetry.
In 2005 the AGS DQD went up one level, by going from a 2D proportions-based Cut-grade to a 3D light performance-based grade. I trust that everyone sees this as an improvement for the consumer, especially since I remember many of us pointing out the errors in the proportions-based system at that time. The DQR remained as it was.
In January 2006, GIA started its own Cut-grade, based upon proportions. Everybody here agrees that it is less strict than the AGS-system, and there is also serious argument about its basics with proportion-grading only, and flawed research.
What you are failing to see is since that time the AGS-DQR has no longer been a direct potential substitute for this new GIA-report. Thus, from a competitive point-of-view, it is logical that AGS was going to re-think the DQR and introduce a new system for it which, as-before, is less stringent than the DQD, but better than the GIA-report.
Well, here we are, this is the new DQR. Just like GIA, it is proportion-grading again. Polish and Symmetry are used in the same way as with GIA. But unlike GIA, these proportions are based upon the 3-dimensional research that is the basis of their superior DQD. Whichever way you turn it, this is a product positioned directly opposite the GIA-report, only stricter in some areas.
The introduction of this product is entirely logical from a competitive point of view, and one should not be surprised by it.
As I am not going to use this new DQR, I see no reason to defend its pros nor cons. But there is no ground to misuse this introduction to create a storm of unnecessary unrest and misinformation.
Live long
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Paul is correct in pointing out my ignorance of the distinction between the various types of AGSL reports.
It seems this is adding a cut standard to a report where there was previously none.
The new format is ''parametric based'' similar to the basis of HCA and GIA''s Facetware, with an overlay of defined painting and digging and rather tightly defined upper and lower girdle ranges. The new format is generally more strict than GIA''s parameters.
Andrey kindly changed the name of the thread.
Meanwhile there is a discussion going on via email, with the various painting and digging and their impact on the proportion ranges etc.
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Since the early 1990’s, my old firm AGA was using the AGA Cut Class grading system which was, and still is, parameter based. Hundreds of appraisers around the USA, many diamond websites and users all around the world have adopted this logical and simple system for grading and teaching what constitutes the level of quality in cut grading rounds and nearly every fancy shape diamond. DiamCalc by Octonus offers the AGA Cut system right in its software. I understand ImaGem, Inc. uses a refined version in its software as well. The HCA is parameter based and works nicely for many consumers. Proportion based grading of cut quality has been around longer than the AGSL has been in existence. They did not invent this wheel, but have done a great job of promoting the idea to the diamond trade and the consumer. What AGSL has done is liberalize their “strict” system to make it feel better for the range of potential customers considering using the AGSL. I took a lot of flack for parameter based grading while AGSL claimed they had a more refined, "better" idea". Has the idea backfired as they find it increasingly difficult to make more customers? The diamond trade tends to like secrecy and smoke and mirrors. Open grading schemes look super to consumers, but dealers must feel they can compete or they will opt for less open, and more liberal grading scenarios.
The number of people willing and able to pay for top cut diamonds remains a small percentage of the consuming public. If the system is more relaxed, then the range of stones widens and more people might be able to buy an AGSL graded diamond. You’ll still only get what you can pay for, but maybe there will be a larger range of choices. Just remember, as the range of choices is broadened, the finest cuts sort of get mixed in with the secondary and third level cuts now all called by the same “ideal” name.
Polish and Symmetry
The Ideal Cut Grade can have Ideal or Excellent polish and symmetry
An Excellent Cut Grade can have Ideal or Excellent or Very Good polish and symmetry
Essentially, polish and symmetry grades can be one grade lower than the assigned cut grade
This is fine with me. Makes sense
Table Diameter Sizes
52 to 65%
For the life of me, I can’t agree with 65% tables on the “best” cut rounds. These are NOT the best cut. Pretty is possible, but “best” no way!
Girdle Thickness
The Ideal Cut Grade can have girdle thicknesses of Thin, Medium or Slightly Thick at the ‘valleys’ or ‘scallops’.
Highest grade achievable with up to a 4.5% girdle, at any point, is Ideal
Highest grade achievable with >4.5 to 5.5% girdle, at any point, is Excellent
Highest grade achievable with >5.5 to 6.5% girdle, at any point, is Very Good
Highest grade achievable with >6.5 to 7.5% girdle, at any point, is Good
Highest grade achievable with >7.5 to 10.0% girdle, at any point, is Fair
Highest grade achievable with >10.0% girdle, at any point, is Poor
Extremely thin or very thin girdle, at any point, reduces the cut grade by one grade
OKAY
Weight Ratio
This is factored into the Proportion Charts
I would appreciate someone’s explanation of this factor….
Star Length
All inclusive from 45 to 55%
Lower Girdle Length
All inclusive from 75 to 85%
This is normal and should pose little issue with anyone.
Painting and Digging
Maximum digging of the upper half facets is 3 degrees of azimuth
Maximum painting of the upper half facets is 4 degrees of azimuth
Maximum digging of the lower half facets is 3 degrees of azimuth
Maximum painting of the lower half facets is 3 degrees of azimuth
No problem with Sarin software, but not what I’d do to “grade” a diamond’s cut. If you think it is highly important, I see no harm in using some numbers such as these.
Rounding
Table diameter percentage is rounded to the nearest 1%. 55.4% = 55%. 55.5% = 56%.
Pavilion angle is rounded to the nearest tenth of a degree. 40.74° = 40.7°. 40.75° = 40.8°
Crown angle is rounded to the nearest half degree. 34.24° = 34°. 34.25° = 34.5°
Note: All angles and percentages on AGSL documents are reported to the accuracy of the Sarin DiaMension measuring device, but the above rounding is used for calculating the proportion cut grade.
The Sarin has accuracy issues like all measuring scanners. Why further create erroneous calculations by degrading the errors further with rounding? Just use the numbers as generated and let it be. Rounding does nothing to improve accuracy. It does exactly the opposite.
Culet Size
Highest grade achievable with none, very small, small or medium is Ideal
Highest grade achievable with slightly large is Very Good
Highest grade achievable with large is Good
Highest grade achievable with very large or extremely large is Fair
This is fine
Any standard round brilliant cut outside of any of the above parameters must be cut-graded using the patented AGS Performance Grading Software
What kind of acceptable “system” for grading ROUND DIAMONDS requires use of another system for grading some of them? If a “system” works, then it should work well for 98 or 99 percent comes into it for grading. There should not be any exeption which would other wise grade "ideal" yet not be gradable in this new system.
Glad to hear further comments and take advice. While it might appear I am being negative, I am happy to see cut grading progress as it had been doing. This "new" approach looks to me more like a step back or sidewways and not forward. Just using the parameters above looks much more like the 1990's than what we are going toward in 2009.
The number of people willing and able to pay for top cut diamonds remains a small percentage of the consuming public. If the system is more relaxed, then the range of stones widens and more people might be able to buy an AGSL graded diamond. You’ll still only get what you can pay for, but maybe there will be a larger range of choices. Just remember, as the range of choices is broadened, the finest cuts sort of get mixed in with the secondary and third level cuts now all called by the same “ideal” name.
Are there parameters for Crown height %, Crown angle, and the same for the pavilion? Where are they listed or why are they skipped?
Polish and Symmetry
The Ideal Cut Grade can have Ideal or Excellent polish and symmetry
An Excellent Cut Grade can have Ideal or Excellent or Very Good polish and symmetry
Essentially, polish and symmetry grades can be one grade lower than the assigned cut grade
This is fine with me. Makes sense
Table Diameter Sizes
52 to 65%
For the life of me, I can’t agree with 65% tables on the “best” cut rounds. These are NOT the best cut. Pretty is possible, but “best” no way!
Girdle Thickness
The Ideal Cut Grade can have girdle thicknesses of Thin, Medium or Slightly Thick at the ‘valleys’ or ‘scallops’.
Highest grade achievable with up to a 4.5% girdle, at any point, is Ideal
Highest grade achievable with >4.5 to 5.5% girdle, at any point, is Excellent
Highest grade achievable with >5.5 to 6.5% girdle, at any point, is Very Good
Highest grade achievable with >6.5 to 7.5% girdle, at any point, is Good
Highest grade achievable with >7.5 to 10.0% girdle, at any point, is Fair
Highest grade achievable with >10.0% girdle, at any point, is Poor
Extremely thin or very thin girdle, at any point, reduces the cut grade by one grade
OKAY
Weight Ratio
This is factored into the Proportion Charts
I would appreciate someone’s explanation of this factor….
Star Length
All inclusive from 45 to 55%
Lower Girdle Length
All inclusive from 75 to 85%
This is normal and should pose little issue with anyone.
Painting and Digging
Maximum digging of the upper half facets is 3 degrees of azimuth
Maximum painting of the upper half facets is 4 degrees of azimuth
Maximum digging of the lower half facets is 3 degrees of azimuth
Maximum painting of the lower half facets is 3 degrees of azimuth
No problem with Sarin software, but not what I’d do to “grade” a diamond’s cut. If you think it is highly important, I see no harm in using some numbers such as these.
Rounding
Table diameter percentage is rounded to the nearest 1%. 55.4% = 55%. 55.5% = 56%.
Pavilion angle is rounded to the nearest tenth of a degree. 40.74° = 40.7°. 40.75° = 40.8°
Crown angle is rounded to the nearest half degree. 34.24° = 34°. 34.25° = 34.5°
Note: All angles and percentages on AGSL documents are reported to the accuracy of the Sarin DiaMension measuring device, but the above rounding is used for calculating the proportion cut grade.
The Sarin has accuracy issues like all measuring scanners. Why further create erroneous calculations by degrading the errors further with rounding? Just use the numbers as generated and let it be. Rounding does nothing to improve accuracy. It does exactly the opposite.
Culet Size
Highest grade achievable with none, very small, small or medium is Ideal
Highest grade achievable with slightly large is Very Good
Highest grade achievable with large is Good
Highest grade achievable with very large or extremely large is Fair
This is fine
Any standard round brilliant cut outside of any of the above parameters must be cut-graded using the patented AGS Performance Grading Software
What kind of acceptable “system” for grading ROUND DIAMONDS requires use of another system for grading some of them? If a “system” works, then it should work well for 98 or 99 percent comes into it for grading. There should not be any exeption which would other wise grade "ideal" yet not be gradable in this new system.
Glad to hear further comments and take advice. While it might appear I am being negative, I am happy to see cut grading progress as it had been doing. This "new" approach looks to me more like a step back or sidewways and not forward. Just using the parameters above looks much more like the 1990's than what we are going toward in 2009.
Regular Guy
Ideal_Rock
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Dave...
I''ve three thoughts in response to yours, if you''ll humor me.
I''ll start with your reflection on your own system, and ask something I''ve frequently wondered about:
1) From your system, lifted from this board, I read:
"Pavilion Depth % 42.8-43.2%"
for your 1A Classification. Do you intentionally not include, or translate into pavilion angle...which many include and represent may be more constructive than a percent?
2) Where you say:
3) Dave where you say...
Regards,
I''ve three thoughts in response to yours, if you''ll humor me.
I''ll start with your reflection on your own system, and ask something I''ve frequently wondered about:
1) From your system, lifted from this board, I read:
"Pavilion Depth % 42.8-43.2%"
for your 1A Classification. Do you intentionally not include, or translate into pavilion angle...which many include and represent may be more constructive than a percent?
2) Where you say:
GIA has caused technical problem, I think, with their rounding...and I''m betting AGS is merely causing itself problems by even using the term again. I think they are maybe only describing the basis for which they apply a category, rather than doing any modification to the data...and they do try to review this, perhaps, in the area I have highlighted...but please check me...as I may be wrong on this, absolutely.
3) Dave where you say...
I''m not successfully getting what you mean, and understanding how you''re applying these ideas to what AGS is doing, or how it''s projected dealers will be behaving...so I''d be interested in your clarifying the point.
Regards,
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I used pavilion percentages for all stones and not just round stones. We can very accurately measure the percentage of pavilion depth for any shape, but around the girdle / pavilion junction on most shapes other than rounds there are large ranges of pavilion angles, let alone pavilion break angles lower on the pavilion. Too much data makes for a system which cannot function. Pavilion precentage may be overly simple for some technical reasons, but it works nicely in the real world.
The rounding issue may be something that AGSL or one of their knowledgeable users can comment on. Mathmatically, rounding contributes to ease of putting down numbers, but detracts from accuracy. If they are rounding without using the rounded data, one must ask, why are they doing that? I''m not a math scholar, but rounding either increases inaccuracy or adds confusion. Where is the simple benefit we assume they meant to provide?
Your last question about what AGS is doing. I feel they are giving us an open system which is more liberal and simple than the eariler light performance version. The reasons can be many, but I feel an important reason to go this way for AGSL is to get more volume through the lab. Liberalizing the "standards" is something dealers will like. They will give slightly less well cut stones to AGSL and everyone will learn to love the newest version of AGS 0 Ideal. There still will remain the premium for the truly finer AGS0 cut stones, but the consumer will have to hunt more diligently for them. Dealers like to make consumers work a little, whether it is a price thing or a quality thing, the profit is derived from selling a diamond for a few dollars more than it cost and if one can get yet a few more bucks on top because of mystery grading, then that will make most sellers even happier. That''s capitalism and business. It isn''t as bad as any of the alternatives, but one must protect oneself when buying.
I think I''ve given you driect replies to your questions. I''m not happy or unhappy about the new "system". It probably will succeed in taking its place in the diamond grading community. It does bother me a bit that it is more a rehash of long existing knowledge than making progress. The market is highly resistant to objective standards with real teeth in them. It prefers a larger zone of "Ideal" or "Excellent" than ought to be given. If I hadn''t seen it myself for more than 40 years, I wouldn''t be making this sort of assertion. Without experience in this market, one could hardly know the real goings on of the trade. Pricescope is an entirely different media than what passed for the diamond business for decades and knowledge is the important thing we all can gain here.
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Hi Dave. Per my first post in the thread there are 14 charts, one for each table size 52-65, with lookup c/p combinations to see resultant grades.
I checked and nothing with 65T receives the top grade. Only seven possibilities for the top grade exist at 62T. Sixty-three possibilities exist at 56T. This mimics the cut guides they released for the light performance grade.
Table/Crown/Pavilion/Girdle combinations that result in a diamond that is overweight (spread too small for weight) are penalized. As we know, the PGS software uses a 5% weight ratio.
The CA rounding is unfortunate. I believe the decision to do this was in the interest of keeping the system simple on the charts. The other numbers are pretty standard. I'm glad they're not rounding PA or minor facets.
As you say, RBCs with tables smaller than 52 and larger than 65 are not covered under this system. I don’t know that many such stones would receive Ideal in the light performance system (none >62T) but some near 50T may. There are also diamonds with lower halves and stars outside this range that would of course. I suspect they wanted to keep this watered-down report simple to comprehend and apply (just as the former DQR was simple) ergo 1 page of instructions and 14 charts. If a diamond is off the chart it must be measured in the more sophisticated DQD/3D system.
Unlike some of us who meet at the PS watering hole it's going to take years for most people to realize that two dimensional cut grading is intrinsically flawed. But this is the kind of system the trade has told AGS it wants, so it has been made available for a lot of the round makes you typically see. It's obviously nowhere near as nimble or specific as the DQD 3D light performance system which can evaluate any round brilliant with any proportions and any table size and any painting/digging and any star/lower half lengths.
Anyone can view the Gold system here
http://www.agslab.com/trade_research_and_development_proportion_based_cut_grade.php
Regular Guy
Ideal_Rock
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Serg,
With JP''s post and link...above and here...I think that with the charts having been made public...having permission becomes moot...not relevant.
I can''t cut & copy the text at their front page, but the claim is that the proportions based system is based on their 3D system....as had been my original assumption and hope.
I read you may have discerned particular crown & pavilion combos otherwise?
Can you explicate now?
Regards,
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Dear Ira,
I can not understand your question, I hope sergey can?
Dear All,
We have had discussions off line about the digging and painting rules, which apparently are or are very similar to those developed by GIA.
Thank heaven the AGS Crown and Pavilion angle parameters are much tighter than GIA''s Excellent - so what I am about to discuss should not have anywhere near the potential for misleading consumers as the GIA system.
Many people have wondered why there is a weight saving to be had with painting and digging - one question is:
If it saves weight - why are not all stones treated that way?
I hope this picture explains why
This stone has a dug crown and a painted pavilion.
There are 4 possible options and this excellent article from brian Gavin shows the variants and ASET images for the results.
This link comes in on about page 3 I think
http://journal.pricescope.com/Articles/45/2/Visible-Effects-of-Painting--Digging-on-Superideal-Diamonds.aspx
I can not understand your question, I hope sergey can?
Dear All,
We have had discussions off line about the digging and painting rules, which apparently are or are very similar to those developed by GIA.
Thank heaven the AGS Crown and Pavilion angle parameters are much tighter than GIA''s Excellent - so what I am about to discuss should not have anywhere near the potential for misleading consumers as the GIA system.
Many people have wondered why there is a weight saving to be had with painting and digging - one question is:
If it saves weight - why are not all stones treated that way?
I hope this picture explains why
This stone has a dug crown and a painted pavilion.
There are 4 possible options and this excellent article from brian Gavin shows the variants and ASET images for the results.
This link comes in on about page 3 I think
http://journal.pricescope.com/Articles/45/2/Visible-Effects-of-Painting--Digging-on-Superideal-Diamonds.aspx
strmrdr
Super_Ideal_Rock
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Even if the proportion system is reasonable a AGS Ideal DQR does not equal a AGS Ideal DQD and vis-versa and there will be massive confusion.
A stone may score Ideal on both but looking over the available information there are several combos that wont.
For example 56,41,35 is Excellent on the DQR and several examples are available of stones getting Ideal on DQD with this combo but not all do.
A stone may score Ideal on both but looking over the available information there are several combos that wont.
For example 56,41,35 is Excellent on the DQR and several examples are available of stones getting Ideal on DQD with this combo but not all do.
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Dave I do not think the issue is as simple as Sarin''s rounding (after all on brder line calls AGSL have Helium''s to check those stones with).
The issue is the clients sending the stones and the arguements when they say "it was XYZ on my scanner".
Besides the big issue with GIA''s Facetware is they use steps of 0.2 degrees for pavilion angles.
Scanners measure pavilion angles much more accurately than they measure crown angles. (Pavilion and crown %''s are also very dodgy from most scanners - especially Ogi - so i am glad they are not using %''s)
There is a roughly 5:1 relationship between the effect from the crown angle to the effect of the pavilion - so infact the rounding is really practical given that each step makes one little box as John has pointed out. If they did round the crown to 0.1 then the parameters would be a nightmare.
But here is another problem that i just thought of:
AGS 0 proportions became a default system used in many countries by people who had no idea what the initials even stood for.
The change to the light performance system did not stop that - as we discussed at length in the thread re- John''s interview on the AGS site.
"Ideal" has become a generic term - and my reasoning says it was because anyone who scanned a stone and printed a Sarin or Ogi report could select the drop down that said this piece of dross is an AGS Ideal Cut. (Of course there are other reasons - but i believe this is #1).
It is quite easy to program this new system into any scanner (DiamCalc does this for AGA, GIA old, GIA new, AGS old and AGS cut parametrs - all for a few hundred bucks)- and there will be new justification for many in the market place to be doing it.
anyway - enough rambling
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Dave,
You are raising questions and criticism based upon incomplete information. I think that you have simply become nervous because of another error of Garry''s.
Garry,
I have re-read this thread and the private communication that you have refered to, and find that you have posted another elementary error in this thread. Look at this:
Peter told you that in the comparison between the AGS-DQR with the GIA-system, there are less possible combinations of AGS-DQR-Ideals than GIA-EX, but there are more AGS-DQR-Excellents than GIA-EX.
You have incorrectly translated this into AGS extending the range of AGS-DQD-Excellent to a bigger AGS-DQR-Excellent-range.
I must say that I am not used to this from you, Garry, two elementary errors in one thread. Are you sleeping enough lately?
Live long,
You are raising questions and criticism based upon incomplete information. I think that you have simply become nervous because of another error of Garry''s.
Garry,
I have re-read this thread and the private communication that you have refered to, and find that you have posted another elementary error in this thread. Look at this:
The highlighted above is an incorrect translation of the information that you got from Peter Yantzer.
Peter told you that in the comparison between the AGS-DQR with the GIA-system, there are less possible combinations of AGS-DQR-Ideals than GIA-EX, but there are more AGS-DQR-Excellents than GIA-EX.
You have incorrectly translated this into AGS extending the range of AGS-DQD-Excellent to a bigger AGS-DQR-Excellent-range.
I must say that I am not used to this from you, Garry, two elementary errors in one thread. Are you sleeping enough lately?
Live long,
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Paul I have no agenda here - I am trying to report with neutrality what I observe and comprehend.
The range of AGS EXCELLENT is what I wrote. Not IDEAL.
The range of AGS Excellent is indeed considerably larger than the range of GIA Excellent. You assume that I made this statement in a negative way - you assume wrongly.
AGS has pushed its Excellent well down into very shallow crown angles - I have no problem with this - as long as they adjust the girdle thickness to minimise the risk of chipping. GIA on the other hand has tried to follow the laws of nature - but has been constrained by the decades of teaching and training and has clipped the ranges of beautiful alternative diamonds that I have been fighting to make available - the BIC''s and FIC''s.
Like many of you, I have had a busy week - this arrived in my lap unannounced just the other day - I am still learning about it all - and sadly - my off line questions and my obvious and openly admitted ignorance of the difference between a DQD and DQR made a fool of me. I have sold only 1 or 2 AGS graded diamonds in my life. Geographically they are not suited to my world. But if I were in USA I would imagine I would deal in many and be more aware of the variety of reports. Whip me for that.
I have no problem with AGS growing their business - AGS run an excellent lab focused on 1/2ct to 1.5ct stones - GIA stones I see below 1ct indicate they have QC problems that one only hopes they will fix by running labs outside USA.
Peter knows that I believe AGS is silly to have such a strict pol and sym standard - GIA got that right. I believe they should also relax the standard for the DQD - and probably take the DQR back another notch.
If AGSL want to get a share of the EX EX EX market then let them go for it.
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Regular Guy
Ideal_Rock
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Look what happens after I get even a little shut eye!
Garry, I'm sorry what I wrote was confusing...where you say:
"Dear Ira,
I can not understand your question, I hope sergey can?"
Maybe the problem is that I edited too much the fullness of the text where Sergey replied, so I'll lift the whole thing now...except to add this explanation.
It sounds like the main area you are interested in this change of systems for AGS is with digging & painting. Me...I'm a more simple man. For years I've been satisfied, stupidly or not, to make buy recommendations based on your HCA...possibly now with an idealscope. So for my money...I had thought that if AGS brings forward a new system that's no worse than HCA, but at least is based on having measured the diamond with accuracy...and then having applied a proven HCA type set of crown & pavilion combos that are proven (ala the 3d)...then this would be an improvement over what GIA is doing on a couple of counts. But...as this conversation developed, I had been lead to believe that the crown & pavilion combos referenced in this new system do not even match the more recently developed system, from this exchange with Serg:
Anyway...if everyone is satisfied that the combos embedded in the recent AGS system match pretty well to the now published crown & pavilion combos in the brand new system...it was the only issue I was raising.
Garry, I'm sorry what I wrote was confusing...where you say:
"Dear Ira,
I can not understand your question, I hope sergey can?"
Maybe the problem is that I edited too much the fullness of the text where Sergey replied, so I'll lift the whole thing now...except to add this explanation.
It sounds like the main area you are interested in this change of systems for AGS is with digging & painting. Me...I'm a more simple man. For years I've been satisfied, stupidly or not, to make buy recommendations based on your HCA...possibly now with an idealscope. So for my money...I had thought that if AGS brings forward a new system that's no worse than HCA, but at least is based on having measured the diamond with accuracy...and then having applied a proven HCA type set of crown & pavilion combos that are proven (ala the 3d)...then this would be an improvement over what GIA is doing on a couple of counts. But...as this conversation developed, I had been lead to believe that the crown & pavilion combos referenced in this new system do not even match the more recently developed system, from this exchange with Serg:
Now...if Sergey's point is more that the original set of parameters were problematic anyway...we are back to square one.
Anyway...if everyone is satisfied that the combos embedded in the recent AGS system match pretty well to the now published crown & pavilion combos in the brand new system...it was the only issue I was raising.
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Dear Ira, Sergey is tavelling at present - I am sure you can answer your own question by counting the boxes here.
http://www.octonus.ru/oct/mss/gia-agspgs.phtml
But do remember that there are 2 AGS boxes for every 1 GIA because GIA rounds to a whopping 0.2 degrees for pavilio angle.
I think the issue for Pricescope crowds is between AGS Ideal and AGS excellent and where the boundaries lie for things like steep/deeps etc. Again I have not had time to do a full analysis - so I will not comment until I have.
Meanwhile i have some more info from Peter that compares the # of each catagory from AGS/GIA - will see if it is appropriate for here.
strmrdr
Super_Ideal_Rock
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I have been running some worst case combos from the charts for ideal and I am not liking what I am finding.
There are several combos that will get ideal that will not get ideal light performance on the 3D system.
That on top of the name confusion is confirming my opinion that it is insane to have the top grade AGS Ideal in both systems!
A cutter could make a fortune cutting these stones and abuse the reputation the AGS Ideal name has earned with the 3D system.
This is not a good thing for consumers.
There are several combos that will get ideal that will not get ideal light performance on the 3D system.
That on top of the name confusion is confirming my opinion that it is insane to have the top grade AGS Ideal in both systems!
A cutter could make a fortune cutting these stones and abuse the reputation the AGS Ideal name has earned with the 3D system.
This is not a good thing for consumers.
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Karl some cutters abused the old aGS parametric system, and many abuse the GIA current system.
Abusers will find some parts of the market will adjust - and when the main buyers are AGS retailers - they are not all that silly - so the market will set different prices.
I imagine the ned result is that when a dealer who knows PGS says the stone is AGS 0 - they will send it in for a Platinum report. Many stones are dinged for not having ideal sym or polish - so they will come away with a Gold report. Overall that is where I believe the lions share of these stones will really come from.
So please do not panic
It will become part of our regular questioning and answering here on Pscope too - just as it will among AGS specialist retailers.
As for some of the badly dug potential combinations - I can not believe that if this becomes a big problem that AGSL will sit by twiddling their thumbs.
I am about to post some stuff from Peter
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Peter spent his night I guess making these bar graphs of the number of combinations.
I added charts from GIA and AGS beside each.
Note that the GIA chart is "Working to Rules" with cut offs that are politically inspired.
Please go open the 57% HCA page and look at the colours I used in HCA - remember that my HCA (and all AGS original material) were the other way around - the natural way. (GIA obviously reversed the pavilion angle axis for political reasons - and sadly AGS has had to follow suit).
What i would like you to note is that I have green arms extending up from each side with a big bad no go zone in the middle. I was shocked when I did this initial work and thought "maybe I should fudge the data" - but what this shows is that AGS is indeed using a parametric system that replicates what happens in nature - it''s physics stupid! (not the economy
So all up - it seems that we can pick some holes and hope AGS will perhaps work on the painting and digging a little more (A big job) - and that might force GIA to change their approach too - which will protect about 35 times more consumers than anything anyone else can do for consumer and retailer confidence. More on that later if I get a chance
I added charts from GIA and AGS beside each.
Note that the GIA chart is "Working to Rules" with cut offs that are politically inspired.
Please go open the 57% HCA page and look at the colours I used in HCA - remember that my HCA (and all AGS original material) were the other way around - the natural way. (GIA obviously reversed the pavilion angle axis for political reasons - and sadly AGS has had to follow suit).
What i would like you to note is that I have green arms extending up from each side with a big bad no go zone in the middle. I was shocked when I did this initial work and thought "maybe I should fudge the data" - but what this shows is that AGS is indeed using a parametric system that replicates what happens in nature - it''s physics stupid! (not the economy
So all up - it seems that we can pick some holes and hope AGS will perhaps work on the painting and digging a little more (A big job) - and that might force GIA to change their approach too - which will protect about 35 times more consumers than anything anyone else can do for consumer and retailer confidence. More on that later if I get a chance
strmrdr
Super_Ideal_Rock
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Date: 10/16/2008 9:58:24 PM
Author: Garry H (Cut Nut)
Karl some cutters abused the old aGS parametric system, and many abuse the GIA current system.
Abusers will find some parts of the market will adjust - and when the main buyers are AGS retailers - they are not all that silly - so the market will set different prices.
I imagine the ned result is that when a dealer who knows PGS says the stone is AGS 0 - they will send it in for a Platinum report. Many stones are dinged for not having ideal sym or polish - so they will come away with a Gold report. Overall that is where I believe the lions share of these stones will really come from.
So please do not panic
It will become part of our regular questioning and answering here on Pscope too - just as it will among AGS specialist retailers.
As for some of the badly dug potential combinations - I can not believe that if this becomes a big problem that AGSL will sit by twiddling their thumbs.
I am about to post some stuff from Peter
No panic here.
If AGS does something I don''t like *cough* *cough* EC/SE grades I just reject it.
I can just as easily reject ideal for rounds. *shrug*
Why should I have trust that they will react to abuse when it was implemented in the first place to kiss up to the trade and gain business and not for the good of consumers?
There is no question that it is a step backwards from the 3D based system.
adamasgem
Brilliant_Rock
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Garry, I am not 100% sure, but I do not believe that the highlighted is correct..
The way I understand it, confusing as it might seem, "0" (1,2,3 etc) is NOW reserved solely for the light performance report, and the NON LIGHT PERFORMANCE, parameter based system will oly use IDEAL, EXCELLENT, Very Good, Good, Fair and Poor nomenclature only.
IDEAL (Gold) is not necessarilly equal to IDEAL 0 (Platinum)
The new AGS GOLD charts can be compared 1 to 1 with the published GIA charts, whereas the AGS Platinum chart guideline boundaries were only indicative of the approximate BEST grade possible for parameter sets averages.
adamasgem
Brilliant_Rock
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Sergey.. In the PGS light performance chartI believe it was meant to portray the BEST possible grade, NOT A GUARANTEE, where in the NEW GOLD parameter chart, it IS the grade, based on parameter averages.
TWO different meanings, I believe, hence the confusion.
It may also go to "prove" , so to speak, the light performance variance that might be expected within a box, as the VG box allows for a wider range of assymetry than does the PGS, and you are probably sitting on a ridge.
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Marty I have had a few more days to be a bit more clear now - if cutters have Ideal to fall back on there could be more cutters attempt to make AGS 0 - and if they have some doubts they would currently send the in doubt stone to GIA (or another lab).
But what Sergey has posted shows that this may not be so - the PGS software does not appear to line up with the new parametric grades (AGS PGS 0 to AGS VG is not a cusp issue - it is a long way away). Peter is away for a few days and many manufacturers in India (where Sergey is right now) want to know what to do. The chart that Sergey has shown above is the basis of the new software that will be implimented as part of Octonus and Lexus'' service to their clients.
I hope Jason quick can give us a behind the scenes explanation while Peter has a well earned break?
adamasgem
Brilliant_Rock
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Garry.. In my opinion, a purely non rayraced parameter based system, put in place to be an alternative to GIA, should NOT HAVE USED the "Ideal" nomenclature, because of the confusion.
Remember, Garry (and Sergey) a purely parameter based system is going to be different than one based on defined metrics for a specific diamond, because it has to take into account the possible variables (like symmetry) which have been LOOSENED in this system.
adamasgem
Brilliant_Rock
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RE: "But what Sergey has posted shows that this may not be so - the PGS software does not appear to line up with the new parametric grades (AGS PGS 0 to AGS VG is not a cusp issue - it is a long way away). "
There are two things going on Garry, in the Performace based system AGS IDEAL REQUIRES IDEAL POLISH AND SYMMETRY, in the parameter based system it does not.
Secondly the metrics are derived differently, one looking at the actual stone and two tilts and the other looking at averaged, rounded parameter sets evaluated over multiple tilts and the weighted, one would EXPECT differences, and unless you have done the work, I don''t see how beating up about possible ridgelines being "inconsistent" is really important or productive. If the nemerics say an Ideal is an 0.499999 deduction and an EX is up to a 0.9999999 deduction and a VG is a 1.000000 deduction, for example, what looks like two grade difference could easily be one grade, i.e. 0.5000001 difference, truncated and resulting one set being just over the edge, so don''t give me any crap about cusps
We see the same effect every day in color grades, where the net results may show two letter grades, where reality is they are separated by one grade and a smidgen.
Do you understand, even though you or Sergey may not like it.
This is what happens with an arbitrary quantization of the contours, the breakpoint is really somewhere in between sets with differning grades. You have four points making the" box", do all of them have to give the same result, or do you use the results from the midpoint.
It is a different metric, period.
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I hear you Marty - but the difference in PGS results from symmetry is far less than anything I expect you could imagine. I have seen many examples of it when buying.Date: 10/17/2008 6:58:16 PM
Author: adamasgem
RE: ''But what Sergey has posted shows that this may not be so - the PGS software does not appear to line up with the new parametric grades (AGS PGS 0 to AGS VG is not a cusp issue - it is a long way away). ''
There are two things going on Garry, in the Performace based system AGS IDEAL REQUIRES IDEAL POLISH AND SYMMETRY, in the parameter based system it does not.
Secondly the metrics are derived differently, one looking at the actual stone and two tilts and the other looking at averaged, rounded parameter sets evaluated over multiple tilts and the weighted, one would EXPECT differences, and unless you have done the work, I don''t see how beating up about possible ridgelines being ''inconsistent'' is really important or productive. If the nemerics say an Ideal is an 0.499999 deduction and an EX is up to a 0.9999999 deduction and a VG is a 1.000000 deduction, for example, what looks like two grade difference could easily be one grade, i.e. 0.5000001 difference, truncated and resulting one set being just over the edge, so don''t give me any crap about cusps
We see the same effect every day in color grades, where the net results may show two letter grades, where reality is they are separated by one grade and a smidgen.
Do you understand, even though you or Sergey may not like it.
This is what happens with an arbitrary quantization of the contours, the breakpoint is really somewhere in between sets with differning grades. You have four points making the'' box'', do all of them have to give the same result, or do you use the results from the midpoint.
It is a different metric, period.
But I do understand where you are coming from - and it is of course a factor.
But let me try to explain again why I think that Sergey makes a point that is not an attack on AGS - it is advice / question from manufacturers.
A stone comes off the wheel - it is run thru PGS, has a AGS0 for light performance - and has pretty good sym and polish.
Manufacturer must decide to send or not send it to AGS -so somoene must spend 1 hour looking thru a microscope to see if it will pass IDEAL sym and poish.
Now they could simply shoot it thru after a good look with a loupe knowing that if it does not get AGS 0 it can get AGS Ideal as a safe fall back.
The trouble is the quick PGS test is not a safe fallback. So AGS will not get the doubling of business it is aiming for and a simplification for their clients at the cutting side.
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