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Why is this an AGS 0

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darwin1534

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I''m looking at a AGS graded diamond with the following specs
AGS graded on June 21 2005
Cut grade 000
Color G
Clarity VS2
Table 55%
Depth 61.8%
Pavillion angle 40.6
Crown angle 36.3
girdle .6% - 2.8%
fluorescence Neg.
HCA score of 2.0

The stone displays the hearts and arrows effect, and seems to sparkle more then most non ideal diamonds that I''ve seen. The diamond is cheaper by ALOT ($6350)then the other ideal diamonds in the area and I think that this is why. My question is how come it''s still rated a cut grade of 0 when it has a Crown angle of 36.3? It''s my understanding that the cut grade for a crown angle for a 0 grade is 33.7-35.8? I like the stone but the crown angle is bothering me?

Thanks
 

Garry H (Cut Nut)

Super_Ideal_Rock
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There is no upper limit on crown angle - it could be over 37 since they changed the system to performance and away from parametric 2 years ago.

Read this
http://diamonds.pricescope.com/crn_pav.asp
They took a few years, but they caught up. GIA also accepts over 36 crown angle as excellent.
 

darwin1534

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The Document that I have is a fax, but I''m pretty sure it''s 36.3. I understand that AGS is now more performance based then proportion. Under cut grade what is the proportion factors then? I don''t need a super ideal diamond, I''m just looking for something with more sparkle then the average diamond. So should I just trust the AGS cut grading of 000?
 

Paul-Antwerp

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I am just wondering that it could be 35.3 (guesswork based upon total depth and table size without any calculation).

Proportion factors is grading factors that do not deteriorate the light performance, but could deteriorate the durability of the stone, like too thin a girdle, for instance.

Live long,
 

pyramid

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I noticed in that link I posted that No.2 is Proportion factors.
 

JohnQuixote

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Date: 4/10/2007 8:23:12 AM
Author: darwin1534
The Document that I have is a fax, but I'm pretty sure it's 36.3. I understand that AGS is now more performance based then proportion. Under cut grade what is the proportion factors then? I don't need a super ideal diamond, I'm just looking for something with more sparkle then the average diamond. So should I just trust the AGS cut grading of 000?
The cut guidelines AGS provides to manufacturers predict 40.6/36.3 with 55T to be on the border of 0 and 1 in light performance.

As the others have indicated, there's not a 'range' limit to proportions anymore; it's how the diamond performs when individually analyzed at the lab. I'd imagine you see a lot color in the sparkle of this diamond, as smaller tables/high crowns give greater fire in the balance.

'Proportions Factors' on the new AGS DQD is no longer an evaluation of optics. It's assessing whether the diamond weighs too much for its spread, durability of the girdle, whether it will show a girdle reflection too quickly when tilted, culet off center, etc.

Here is a link describing the differences between old and new AGS reports.
 

darwin1534

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So if this is on the low end of light performance for a 0, could the average person tell much difference in a high end of light performance 0? How about just a non ideal "good" cut diamond?
 

RockDoc

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Date: 4/10/2007 11:22:51 AM
Author: darwin1534
So if this is on the low end of light performance for a 0, could the average person tell much difference in a high end of light performance 0? How about just a non ideal ''good'' cut diamond?
RE: Average Person


Maybe....but maybe not. Untrained, non expert eyes don''t always pick up the minor variances between diamonds that a well trained and experienced eye can. The "taste" test would be to see this stone next to one that is more in the "sweet spot" of the AGS grading and make the comparison visually.

Sometimes you also need many varying light environments to do this well, as some diamonds will have more light return with different light envorments. Factors are color temps, items of color near the stone, UV presence, diffused lighting etc.

Rockdoc
 

JohnQuixote

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Date: 4/10/2007 11:22:51 AM
Author: darwin1534

So if this is on the low end of light performance for a 0, could the average person tell much difference in a high end of light performance 0? How about just a non ideal 'good' cut diamond?
At such a high level the perceptual differences are usually about character, not appeal. For example - a greater balance of fire in X diamond, a greater balance of brightness in Y diamond, greater contrast effects in Z diamond: All equally attractive.
 

pyramid

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Are you able to see the diamond for yourself at the moment.



Read again and see that you have seen it. If you feel uncomfortable just keep looking, it is better than feeling you are stuck with a diamond you do not want.
 

Paul-Antwerp

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Date: 4/10/2007 11:22:51 AM
Author: darwin1534
So if this is on the low end of light performance for a 0, could the average person tell much difference in a high end of light performance 0? How about just a non ideal ''good'' cut diamond?
It is incorrect to assume that, when a diamond''s proportions are close to the borderline between AGS-0 and AGS-1, this stone is at the low end of light performance for a 0.

As a matter of fact, within the range of AGS-0, the absolute best light performance is actually close to the borderline.

Live long,
 

pelicano

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Proportion should theoretically affect the visual performance of the diamond, but it is not so simple as just saying that anytthing above some angle will not look good - it depends on how it plays together with other parameters of the stone.
 
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