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AGS0 Princess Cuts

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WinkHPD

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Date: 10/22/2005 4:11:42 PM
Author: RockDoc

So far from what I''ve seen is that I''d recommend the AGS 0 grading to be sub divided, possibly a grading of AGS0-a / b and c that would be a little more discriminating of the differences. The 0-a 0-b and 0c perhaps honing in on the variances that do genuinely exist.


Rockdoc

I pray to all the deities of all the worlds religions that this NEVER comes to pass!!!!!!!

Already there are way too many already who buy only the paper, regardless of how the diamond actually looks. Some of the world''s most beautiful diamonds are virtually unsaleable as they are branded with AGS 1 cut grades. Too valuable to sell for the same price as an AGS 5 (about the average that we see currently on princess cuts for example) they languish in the safes of Jewelers who bought them for their beauty, unsaleable to those in search of only the most sought after AGS 0.

Now you would create a new brand of pariah, the "lowly" AGS 0c. These "horrible" imposter class AGS 0''s would be unworthy for the paper chaser to even consider. Unless of course you are willing to sell them below cost, since they really have no premium value, not like a "real" AGS 0a.

Please, all ye Deities, assist this poor supplicant in his prayers. Please let beauty be recognized for beauty''s sake and cast out this vile hairsplitting devisive suggestion! Please let this suggestion die a quick and painless death, may it please the Deities that it be born still and silent, never to cause needless pain to the poor jewelers who strive only to bring beauty to the worlds diamond buyers. (And while you are at it, could you please smite any jewelers who are not worthy to do so!?)

Wink

P.S. The above written with some humor intended, some actual prayer intended and much more than a little truth expressed. I have had AGS 1 princess cuts that I thought more beautiful than AGS 0 princess cuts that were incredibly difficult to sell on the net and sold to the first looker in-house as the beauty was way stronger than the paper.

While in truth, there is much to like about the GIA research and grading system, ie, if it looks good, sell it (a gross over simplification, please do not pillor and post me for my early morning humor, I will only plead cough syrup as a mitigating factor), I prefer the more quantifiable work being done currently by the AGS. I would prefer however that we not get into forty cut grades and subgrades and then jump to an even more unmanageable quantity when we discover how to further subdivide the subdivisions. At some point we must look at the stone and know with our hearts, does this thing sing or not?

To be able to do the research will be for some an interesting excercise and may lead to the ability to create even more beautiful diamonds. But to foist this knowledge into an already complex grading system will serve only to futher confuse the poor guy who only wants to buy a beautiful diamond for his lady. Please, let the research continue, but let''s keep the measurements and results quantified into a fairly easily learned system for the lay person. After all if I had to learn doctorate level physics to buy a car, I should probably still be riding my bike...
 

Rhino

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Date: 10/22/2005 1:44:12 PM
Author: Midnight
To Steve, Bill ...

or any vendors that might have seen and examined both the Infinity AGS 0 princess and the unbranded ones, can you please elaborate on your experience and if there is there a visual difference between them? Was there any consistent pattern on the IS, ASET, or BS that distinquish one from the other?
Hi Midnight,

At this point it appears one of the primary differnces is the amount of chevrons on the pavilion and perhaps the intensity on which light is exiting the stone. High intensity doesn''t always equate to most beautiful. It depends on the personal preferences and taste of the individual. The below graphic demonstrates the difference between a 2 and 4 chevron AGS Ideals from the pavilion side. To see the face up effects the virtual models will do the best job of showing you that. This is one of the features seperating the various personalities of AGS Ideal Princess Cuts and stresses the need to *see* in order to determine, that is, if a person has a preference between the personalities of the 2.

This feature (amount of chevrons) is a primary contributing factor in the nature upon which light is reflected back to the eye provided the facets are functioning in thier role as "mirror" (as opposed to facets functioning as windows or leakers). The fewer the chevrons the more of a broad flash you''ll get and with the greater number of chevrons the more pin flash you''ll get.

Hope that helps.

4vs2chevrons.gif
 

Rhino

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Date: 10/22/2005 4:11:42 PM
Author: RockDoc

As far as the BScope goes, for these stones, one needs to thoroughly understand that the analyzer B Scope doesn''t meaurea beauty or attractiveness. This I believe to be the main difference in the varying opinions of B Scope results.

There is however a lot more result to be gathered from the BScope Viewer. This is because the attractiveness of the particular stone can be side by side compared in this tool, with the HUMAN eye, rather than the ''robotic'' eye of the B Scope. For stones that rate a bit lower on the B Scope, I sincerely believe there may be a little more hair-splitting than our eyes can see as compared to the pixel analysis that the B Scope Analyzer when compared with the Viewer instrument.

I want to certainly test more of these type stones before making any conclusive statement of my opinion of any perceived variances. In addition, I want to reconcile the results against the ASET tools ( both hand held and Desktop) and with the 2.4 version of Diamond Calc, the Sarin, my light leakage testing, and the B Scope equipment.
I agree. With all the new equipment and various flavors being offered it is interesting to see how various stones corellate to technology and the tools many use to employ in the purchasing decisions or appraisals. One technology I have been taking a more keen interest in is the MSU softare in both light return and contrast scores and how they corellate to human observation. As your studying RockDoc take note of BrillianceScope results, light retur results via MSU and also contrast scores via MSU. While the Bscope viewer is a useful device in observing the mosaic of light as it is transmitted through the crown don''t limit yourself to this alone. More importantly take the stone into typical office lighting (suffuse overhead fluorescent) and compare the view there as well. Many times the 2 do not always corellate. Ie. there are stones that look GREAT in direct lighting but suffer in the office conditions.


So far from what I''ve seen is that I''d recommend the AGS 0 grading to be sub divided, possibly a grading of AGS0-a / b and c that would be a little more discriminating of the differences. The 0-a 0-b and 0c perhaps honing in on the variances that do genuinely exist.
LOL... I''m with Wink on this one mate. One factor that *both* GIA and AGS systems encourage is the need for the consumer *to see* what it is they are purchasing. Princess cuts aside, consider the *many* appearances an AGS Ideal Round can take on. If they were to make subcategories for each flavor there would be no end to the madness.
37.gif
hehe

All the best,
 

RockDoc

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Rhino and Wink

I think I am in agreement with you more than you realize.

For stones that look incredible but get the AGS 1 seems a bit unfair as Wink mentioned that he saw AGS 1''s that he feels are equal or superior to the AGS 0, one needs to ponder if AGS''s assignment of the 1 cut grade is really proper. It appears to me that such stones should be 0''s but defined based on the "flavor" so that such stones aren''t misunderstood as being less than the cat''s meow, when to the eye, and through an assessment of the beauty they really are.

For the consumer, they seem to want to know more and more about the variances that experts see. The problem here has a lot to do with personal preference. The problem is that personal preference does and isn''t uniform when seen by the eye. There are varying preferences of what is the "best" even between the most astute cutters, sellers, and graders.

It would be great if a certain appearance was unilaterally agreed upon to be superior, but with the varying opinions of preferences, this would most likely be unattainable. But it would be nice to attempt it.

Basically, we don''t have all the reasons why a stone that appears equal in appearance to a 0 would get an AGS 1. Obviously there is a reason that AGS chooses to assign a 1 to a diamond that those dealing in diamonds believe that it is equal or superior. If two stones to the trained and experienced eye, look similar or even better assignin a grading perceived as being lower by the consumer relying on such reports could be a mis-service.

I am certainly in agreement that a stone that deserves an AGS 1 is proper. But based on some of the comment by Rhino, Garry, Steve, and Wink ( or any others that I haven''t named) there are some diamonds that really do appear great that get a 1. I guess either such stones get a zero or we have to educate the buying public that an AGS 1,2 etc, is stilll perfectly acceptable, and not the "kiss of death".

Rockdoc







 

WinkHPD

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Date: 10/23/2005 12:55:54 PM
Author: RockDoc

Rhino and Wink

I think I am in agreement with you more than you realize.

--Snip--

I am certainly in agreement that a stone that deserves an AGS 1 is proper. But based on some of the comment by Rhino, Garry, Steve, and Wink ( or any others that I haven''t named) there are some diamonds that really do appear great that get a 1. I guess either such stones get a zero or we have to educate the buying public that an AGS 1,2 etc, is stilll perfectly acceptable, and not the ''kiss of death''.

Rockdoc


In this case both of the stones that I had that might as well have been "untouchables" for all the internet interest they generated were AGS 1''s for minor polish or symmetry flaws. They still had 0 grade light return and were incredibly pleasing to the eye, which is why they sold so promptly when shown in-house. It is the seeming impossibility of educating the public that AGS1 does NOT equal unworthy that has me so appalled at the very idea of creating sub catagories of cut grades, breaking down even further an already complex system and adding thirty new designations. For a while it seemed that every one was asking about which of the four sub grades of F color is this diamond, but thankfully that seems to have stopped. I would hope that this never even starts with the AGS cut grade scales.

I can just imagine describing a 10-c cut. "Mrs. Smith, here we have a lump of crystallized carbon that wass misshapen even by (Name your preferred Deity). It came from the ground not as a nice Octrahedral crystal with eight perfect sides, but as a dodecatrioxymoronohedral with all of the crystal faces looking like one of the wierd houses at Knots Berry Farm. Look how nicely the girdle plain is set at 11.5 degrees angle to the table and the crown ranges from 2.3% to 12.6% and we actually have seventeen different pavilion angles depending on which alchoholic beverage the faceter was drinking at the time the diamond was faceted. Yes ma''am, and you just don''t get to see a 14.6% culet these days, now there is a lost art being revived, and look, it is at an 8% angle to the girdle, but in the opposite direction of tilt to the table, otherwise it would be a 10-b.

I doubt that you can even begin to imagine the horror with which I read your post this morning after a long evening with little sleep and that which I did have mixed with the wierd variety of seemingly real nightmares brought on with the drugs I am taking for my cough. I went to the bathroom twice to wipe my face and came back each time to find it was real and I was not dreaming, yet it seemed so surreal that I was not sure I did not dream all of this until I got to my office a few minutes ago and found it still here.

I am glad that you are in agreement with us that many stones that may not look extraordinary on paper actually do so in real life, and I urge you PLEASE, never to propose such a horrible thing again. Now if you were to do research that would show people how to select AGS 1''s, 2''s and 3''s that look FANTASTIC, then I would support you whole heartedly as that would actually benefit the consumer and the vendor alike, especially those who did their homework so that they could ferret out the bargains. THAT is research that MANY would LOVE to hear about.
While it is true that some AGS 0 diamonds will not look as good as others, I think that you will find that the VAST majority of AGS 0 cut diamonds are extraordinary when comparred with the normal cut stone, whether princess or round. I have an AGS 5 here that is a nice enough looking stone, provided you don''t put it side by side with an AGS 1 or 0, and even the worst AGS 0 will normally look WAY better than the best AGS5. Now there is an oxymoron for you, "the worst AGS 0". I have seen some I like better than others, but I have never seen one I did not like.

Wink
 

Rhino

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Wink ... you crack me up.
9.gif


We''re so on the same page. Matter of fact I LIKE stones that have the "0" light performance and may take a knock on polish/symmetry to get the cheaper price as those are factors that do not impact the beauty!
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Bring me AGS 1''s, 2''s and 3''s all day long as long as the stone has it where it counts most.
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Rhino

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In case anyone''s having probs with the Gem Advisor here are the 4 and 2 chevron stones turned face up in office lighting. These differences can be observed with the eyes as well. Hope this helps.

4vs2chevron.gif
 

Garry H (Cut Nut)

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Good stuff you guys.

May I repeat my warning that fancy shapes should be examined over a range of rotation / tilting - and not just face up (which works fine with almost all rounds except fisheyes).

I think you will find that is the problem with the BScope.

In DiamCalc / Gem adviser the most valuable info is the stereo (2 eyed) data through a range of tilting - for both contrast and light return.

I am pretty well ignoring other data these days.


And re the AGS 1''s etc - if Peter had a ''voice'' here, i think he would say that he would prefer to give AGS Excellent polish and Sym AGS0 also. But he must grade to the standards set by their steering committee.

The only thing I would warn people about is I do not like thin and very thin girdles on square stones.
 

Garry H (Cut Nut)

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Rhino, and RocDoc, here is a little experiment if you wish to try it.

Take stones with AGS 0 light performance with extremely good and extremely bad BScope scores.

Run them on Diamcalc / Gem adviser and compare the Light Return mono (like the Bscope) for whole crown (top left) to Light Return Stereo whole crown tilting thru 30 degrees.

Do the same for contrast mono and tilting thru 30 degrees. (I still do not really like the way DC measures Contrast)

I wonder what you might find?

AGS currently do thier testing over a 45 degree rotation - which i think is too much - it is more than people usually do.

But if this was cosine weighted (anyone got a link to the GIA wLR page explaining that term?) then i do not see why it should not be included all the way to 90 degree rotation, combined with surface area weighting.

But if this was a test being performed then I think it is even more important that the comparison for visual effect at oblique angles be always compare to the surface area of a Tolkowsky round (t=1.00).

But that would involve a huge change of tack for AGS.

(BTW the term is TACK and describes one of the two ways to change direction when sailing - the other is JIBE. Often people use TACT and this I believe is wrong)
 

WinkHPD

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Date: 10/23/2005 9:05:11 PM
Author: Garry H (Cut Nut)
Often people use TACT and this I believe is wrong)

Hmm. Maybe I can convince my wife of that, she often accusses me of lacking tact. Can I get you to call her to explain that it is wrong of me to use tact and that I am really just trying to use Australian Rules...

Wink in the morning
 

valeria101

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Date: 10/23/2005 9:05:11 PM
Author: Garry H (Cut Nut)

But if this was a test being performed then I think it is even more important that the comparison for visual effect at oblique angles be always compare to the surface area of a Tolkowsky round (t=1.00).
Wouldn''t this penalize a great deal anything with a lower crown than rounds have? I don''t know about the AGS0 princess cuts, but most others have it pretty flat
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WinkHPD

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Date: 10/24/2005 9:22:49 AM
Author: Garry H (Cut Nut)
Try the golden rule Wink.

Since as a jeweller you have plenty of gold.


Do you remeber it?

Who ever has the gold, makes the rules!

Then I am in serious trouble. She has the gold
 

Rhino

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Good mornin from NY. Thanks for the input Garry.


Date: 10/23/2005 8:43:00 PM
Author: Garry H (Cut Nut)
Good stuff you guys.

May I repeat my warning that fancy shapes should be examined over a range of rotation / tilting - and not just face up (which works fine with almost all rounds except fisheyes).

I think you will find that is the problem with the BScope.
No arguments here. One point about the Bscope that I''ve had to work through in my own mind, especially regarding the princess cuts but it applies to rounds as well ...

At one time a slight conflict of thought ... remember when you and I were going back and forth about the mains? You were arguing obstruction and I was arguing strong reflectors of light (as shown in Bs). We both had valid points. Your argument was based on the obscuration principal now applied in the AGS system however as you bring H&A diamonds into many lighting environments those mains light up, especially upon rocking and tilting, this can also be seen in the DC software besides human observation. My Conclusion: We''re both right.

My thoughts were, if the mains are obscured, when and why should they be illuminated in an analysis? Reason? Those facets will indeed be lit up upon any tilting or rocking. I would view this as a positive because the mains would not normally be lit up unless it was tilted and rocked thus taking into account illlumination that extends beyond the static view. Does this make sense mate?


In DiamCalc / Gem adviser the most valuable info is the stereo (2 eyed) data through a range of tilting - for both contrast and light return.
Amen. With regards to some articles I''m putting together I couldn''t agree more. I''m noting that when I close one eye and do a mono view I''m missing out on a lot of sparkles that the other eye is missing. I do like a mono view though sometimes as it is easier to resolve individual sparkles and flares. Too bad DiamCalc doesn''t include stereo red/blue glasses.
3.gif
One question though: Is the stereo view in DC showing the sparkles the other eye would normally miss? Ie. Is the stereo view showing a *real* stereo view, resolving light return the other eye would normally miss in a mono view?


And re the AGS 1''s etc - if Peter had a ''voice'' here, i think he would say that he would prefer to give AGS Excellent polish and Sym AGS0 also. But he must grade to the standards set by their steering committee.

The only thing I would warn people about is I do not like thin and very thin girdles on square stones.
Gotta admit, this is one feature I like about the GIA system. Polish/symmetry, while traditionally help up as being important, IMO takes a back seat to physical dimentions and optical symmetry. I think you would agree.

Peace,
 

Rhino

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I''ll give your test a shot Garry. My assistant Tim is on vacation this upcoming week so it may be a bit before I get to do this but I will certainly give it a go.
 

Rhino

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Date: 10/24/2005 9:38:15 AM
Author: Wink

Date: 10/24/2005 9:22:49 AM
Author: Garry H (Cut Nut)
Try the golden rule Wink.

Since as a jeweller you have plenty of gold.


Do you remeber it?

Who ever has the gold, makes the rules!

Then I am in serious trouble. She has the gold

LMAO!!! Wink, does she sometimes let you think you''re holding it though?
3.gif
 

Garry H (Cut Nut)

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Date: 10/24/2005 11:27:48 AM
Author: Rhino
Good mornin from NY. Thanks for the input Garry.



Date: 10/23/2005 8:43:00 PM
Author: Garry H (Cut Nut)
Good stuff you guys.

May I repeat my warning that fancy shapes should be examined over a range of rotation / tilting - and not just face up (which works fine with almost all rounds except fisheyes).

I think you will find that is the problem with the BScope.
No arguments here. One point about the Bscope that I''ve had to work through in my own mind, especially regarding the princess cuts but it applies to rounds as well ...

At one time a slight conflict of thought ... remember when you and I were going back and forth about the mains? You were arguing obstruction and I was arguing strong reflectors of light (as shown in Bs). We both had valid points. Your argument was based on the obscuration principal now applied in the AGS system however as you bring H&A diamonds into many lighting environments those mains light up, especially upon rocking and tilting, this can also be seen in the DC software besides human observation. My Conclusion: We''re both right.

My thoughts were, if the mains are obscured, when and why should they be illuminated in an analysis? Reason? Those facets will indeed be lit up upon any tilting or rocking. I would view this as a positive because the mains would not normally be lit up unless it was tilted and rocked thus taking into account illlumination that extends beyond the static view. Does this make sense mate? Yes. Also the 2 eye thing makes it easier for light to be seen that is only obscured by 4 or 5 degrees. Light just behid your right side of head, hits diamond mains and is directed to your right side eye. In a Tolkowsky proportioned stone - you only need 13 degrees of tilt.
For my eye to out side of head dimension of 4mm, at 14 inches view distance, this = 7 degree - so for a tolkowsky stone there is still a 6 degree possible cone of light coming to my eye via the mains star for a tolkowsky stone.
Even more reason to think AGS have it wrong wrong wrong to ban shallow stones because they do not pass a 6 inch head obstruction (40 degree).
One day i will convert you all to the benefits of shallower diamonds.




In DiamCalc / Gem adviser the most valuable info is the stereo (2 eyed) data through a range of tilting - for both contrast and light return.
Amen. With regards to some articles I''m putting together I couldn''t agree more. I''m noting that when I close one eye and do a mono view I''m missing out on a lot of sparkles that the other eye is missing. I do like a mono view though sometimes as it is easier to resolve individual sparkles and flares. Too bad DiamCalc doesn''t include stereo red/blue glasses.
3.gif
One question though: Is the stereo view in DC showing the sparkles the other eye would normally miss? Ie. Is the stereo view showing a *real* stereo view, resolving light return the other eye would normally miss in a mono view? I believe it is Rhino - I made a short movie in DiamCalc and it took nearly twice as long to build in RB stereo mode.



And re the AGS 1''s etc - if Peter had a ''voice'' here, i think he would say that he would prefer to give AGS Excellent polish and Sym AGS0 also. But he must grade to the standards set by their steering committee.

The only thing I would warn people about is I do not like thin and very thin girdles on square stones.
Gotta admit, this is one feature I like about the GIA system. Polish/symmetry, while traditionally help up as being important, IMO takes a back seat to physical dimentions and optical symmetry. I think you would agree. I asked Peter this question when i very first met him years back. As i remember he said he can not usually see the effects of good polish or symmetry on visaul beauty with an inspection of a diamond with his naked eye. I am pretty sure it was ''good'' - but it might have been ''Very good''.

Peace,
How amazing are these guys Rhino? Ask and you have already recieved - stero Red Blue glasses at your service :)

stereoRBGlasses.JPG
 
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