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Will GIA Ideal EX/EX grade as AGS 0??

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JD_MD

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I''m sure this has asked before but will a GIA Ideal cut diamond with EX/EX proprtions meet AGS 0 standards consistently? If one knew the crown and pavillion angles on the GIA cut, would this solidify the answer to the question?

Also, can a comsumer send a stone to AGSL for grading, or is that privledge reserved for those in the trade?

Thanks!
 

Rhino

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According to the current scheme of things ... DEFINITELY NOT. You can have a diamond that currently grades as a GIA Ex/Ex and have lousy optics nad not be an AGS 0. Not to throw a monkey wrench into your research but not all AGS "0" diamonds will be "0" in a month or so as they are changing from proportion based cut grading to "performance based cut grading".

Not sure if a consumer can send a stone directly to AGS. I know they can to GIA so I would assume they can to AGS as well. If someone can confirm, please do.
 

niceice

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Date: 5/25/2005 10:56:02 AM
Author:JD_MD
I''m sure this has asked before but will a GIA Ideal cut diamond with EX/EX proprtions meet AGS 0 standards consistently? If one knew the crown and pavillion angles on the GIA cut, would this solidify the answer to the question?

Also, can a comsumer send a stone to AGSL for grading, or is that privledge reserved for those in the trade?

Thanks!
Not necessarily. AGS is in the process of updating their criteria for the AGS Ideal 0 cut classification. The new scale will not only take proportions into account, but also the visual properties and performance of the stone. This is largely because some of the cutters were cheating the system by producing diamonds with the right average measurements for the crown and pavilion angles, etc. while improperly indexing the facets of the stone which can result in dark areas around the perimeter of the stone - which results in an "ideal cut" diamond that looks smaller than it should. There is nothing wrong with GIA Graded diamonds and there is not a need to necessarily send them to the AGS for confirmation of the grade - just look at the consistency of the facet structure of the diamond by means of a detailed Sarin analysis... A light return analysis wouldn''t hurt either, some of the dealers here on PS have access to a Gem Ex Brilliance Scope as do some of the appraisers... Yes, you may send a diamond to the AGSL for grading as a consumer, but it''s easier for a dealer to do it.
 

oldminer

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AGA is equipped to provide analysis of whether a diamond meets Ideal cut criteria and light performance. We have a new ImaGem installation, www.imageminc.com, that measures and grades light behavior as well as cut. The fees we charge are a whole lot less than AGSL, but the final result is accurate and scientific.

Up to 0.99ct, the public fee is $35, for example. We can also provide Ogi and Sarin full reports at nominal cost. In a very short time, we will also be offering complete ImaGem reports with far more accurate measurements of pertinent features than any offered by dealers or major labs that use Sarin or Ogi. For engineer types who want the numbers, we have highly detailed, repeatable measures that the big labs are not going to offer you.
 

JD_MD

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Date: 5/25/2005 11:15:52 AM
Author: Rhino
According to the current scheme of things ... DEFINITELY NOT. You can have a diamond that currently grades as a GIA Ex/Ex and have lousy optics nad not be an AGS 0. Not to throw a monkey wrench into your research but not all AGS ''0'' diamonds will be ''0'' in a month or so as they are changing from proportion based cut grading to ''performance based cut grading''.

Not sure if a consumer can send a stone directly to AGS. I know they can to GIA so I would assume they can to AGS as well. If someone can confirm, please do.
So a stone that currently grades as an AGS 0 that has excellent facet structure per the Sarin report, an HCA score less than 2 and scores well on the Brilliance Scope should make the "cut" under the new AGS scoring system? Or should one consider waiting for the new AGS standards? It would suck to realize my new 2.25 ct AGS 0 diamond is now an AGS 1 (and worth potentially 10-15% less). Maybe I should wait to purchase?

Also, How will AGS measure optical performance? Will current Brilliance Scope scores approximate the new AGS standard?
 

JD_MD

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Date: 5/25/2005 12:14:48 PM
Author: oldminer
AGA is equipped to provide analysis of whether a diamond meets Ideal cut criteria and light performance. We have a new ImaGem installation, www.imageminc.com, that measures and grades light behavior as well as cut. The fees we charge are a whole lot less than AGSL, but the final result is accurate and scientific.

Up to 0.99ct, the public fee is $35, for example. We can also provide Ogi and Sarin full reports at nominal cost. In a very short time, we will also be offering complete ImaGem reports with far more accurate measurements of pertinent features than any offered by dealers or major labs that use Sarin or Ogi. For engineer types who want the numbers, we have highly detailed, repeatable measures that the big labs are not going to offer you.
Ok, no matter what I purchase...my diamond is going to David''s shop for "the works"!! What is your typical turnaround time? Some vendors offer only a 7-day inspection period.
 

JohnQuixote

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Date: 5/25/2005 12:23:12 PM
Author: JD_MD

So a stone that currently grades as an AGS 0 that has excellent facet structure per the Sarin report, an HCA score less than 2 and scores well on the Brilliance Scope should make the ''cut'' under the new AGS scoring system? Or should one consider waiting for the new AGS standards? It would suck to realize my new 2.25 ct AGS 0 diamond is now an AGS 1 (and worth potentially 10-15% less). Maybe I should wait to purchase?

Also, How will AGS measure optical performance? Will current Brilliance Scope scores approximate the new AGS standard?
We will have to wait and see.

Here is a thread detailing what the new AGS grading report looks like. There is discussion regarding their ASET imagery (light performance assessment) on down in that thread.

It''s pertinent to note that there are fundamental differences that separate Brilliancescope from the Angular Spectrum Evaluation Tool that AGS is using (which is more like ideal-scope). Will BS scores approximate the new standard? Very hard to say - it uses a different premise.

This thread on Brilliancescope is ongoing - and you can find many discussions on that topic with a search.
 

Dancing Fire

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has GIA release their new ideal proportion grade yet? will it be the same as the new AGS?

will GIA go with the id/id terminology in their new system?
 

Dancing Fire

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Date: 5/25/2005 12:23:12 PM
Author: JD_MD

Date: 5/25/2005 11:15:52 AM
Author: Rhino
According to the current scheme of things ... DEFINITELY NOT. You can have a diamond that currently grades as a GIA Ex/Ex and have lousy optics nad not be an AGS 0. Not to throw a monkey wrench into your research but not all AGS ''0'' diamonds will be ''0'' in a month or so as they are changing from proportion based cut grading to ''performance based cut grading''.

Not sure if a consumer can send a stone directly to AGS. I know they can to GIA so I would assume they can to AGS as well. If someone can confirm, please do.
So a stone that currently grades as an AGS 0 that has excellent facet structure per the Sarin report, an HCA score less than 2 and scores well on the Brilliance Scope should make the ''cut'' under the new AGS scoring system? Or should one consider waiting for the new AGS standards? It would suck to realize my new 2.25 ct AGS 0 diamond is now an AGS 1 (and worth potentially 10-15% less). Maybe I should wait to purchase?

Also, How will AGS measure optical performance? Will current Brilliance Scope scores approximate the new AGS standard?
JD_MD
i know what you mean.i''m thinking along the same line.
 

oldminer

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Ok, no matter what I purchase...my diamond is going to David''s shop for "the works"!! What is your typical turnaround time? Some vendors offer only a 7-day inspection period.


We generally have a 1-2 day turn around time. Monday-Friday office hours. Many vendors don''t count the day or two that we have the diamond. It all depends on individual policies.
 

Rhino

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Hi JD,



Date: 5/25/2005 12:23:12 PM
Author: JD_MD

So a stone that currently grades as an AGS 0 that has excellent facet structure per the Sarin report, an HCA score less than 2 and scores well on the Brilliance Scope should make the 'cut' under the new AGS scoring system?
LOL... well ... as thorough an anlaysis as that is (Sarin, B'scope, HCA) that still does not ensure a top grade.
emsmilep.gif


I can link you to a diamond that scores a triple VH on the B'scope, scores less than a 2 on the HCA, yet will still not make top grade. :razz: I can at the same time demonstrate *why* it will not too. Since I can't link from the forum (even for educational purposes) you'll have to send me a pm or email.



Date: 5/25/2005 12:23:12 PM
Author: JD_MD

Or should one consider waiting for the new AGS standards? It would suck to realize my new 2.25 ct AGS 0 diamond is now an AGS 1 (and worth potentially 10-15% less). Maybe I should wait to purchase?
You don't necessarily have to wait IF you are purchasing from or have it inspected by a gemologist who is familiar with all the metrics in the upcoming systems and who know how to determine the features that would cause it to NOT get the upcoming ideal grades. The metrics included in the upcoming GIA system consist of...

a. brightness
b. fire
c. scintillation
d. weight ratio
e. durability
f. polish
g. symmetry

GIA has released specs and data on 15 stones (3 from each of their 5 grades) so I have a basic handle on their upcoming system. I have not seen examples from the upcoming AGS system but have been in discussion with gemologist's from AGS about their upcoming system and am learning more and more about it. Until I see actual examples and/or specs on specific diamonds I am withholding commentary until i know more. As far as I know the metrics for the AGS system will include

Light Performance
a. brightness
b. dispersion (colored light or fire)
c. leakage
d. contrast (in GIA's relates to brightness)
Proportion Factors
a. girdle
b. culet
c. weight ratio
d. durability
e. tilt
Finish
a. polish
b. symmetry



Also, How will AGS measure optical performance? Will current Brilliance Scope scores approximate the new AGS standard?
BrillianceScope analysis will certainly correllate. To what degree remains to be seen on rounds. Recently another appraiser (RockDoc) has posted BrillianceScope results on the new AGS ideal princess and the data coresponded beautifully. I would be quick to point out that while I am a B'scope advocate, the B'scope is not the best tool for determining the metric of *brightness* in the GIA system (and perhaps AGS' as well). It is most useful for determining the metrics of fire/scintillation and particularly in direct light conditions.
 

Rhino

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Hi Dave,

While I''d be the first to recommend you as an appraiser, are you confident enough to know that the Imagem will be able to accurately determine all the metrics that GIA/AGS are examining in their upcoming systems?
 

Paul-Antwerp

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Date: 5/25/2005 1:46:07 PM
Author: Dancing Fire
has GIA release their new ideal proportion grade yet? will it be the same as the new AGS?
No. They have not. It will not be the same as the new AGS, although there are similarities.

Similarity is in the fact that both look at combinations of proportions, and not at each aspect separately.

Difference is in that GIA will work only with proportion parameters, of which most are averaged and rounded, while AGS is working with a ray-tracing program on the 3D-measurement of the stone. Also, GIA will have less possible categories, and the top-grade will be way broader than the top AGS-grade.


Date: 5/25/2005 1:46:07 PM
Author: Dancing Fire
will GIA go with the id/id terminology in their new system?
The highest possible grade with GIA will remain ''Excellent''

Live long,
 

oldminer

Ideal_Rock
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"While I'd be the first to recommend you as an appraiser, are you confident enough to know that the Imagem will be able to accurately determine all the metrics that GIA/AGS are examining in their upcoming systems? "

ImaGem will not measure every possible angle and facet length in order to inaccurately predict light behavior. Instead, ImaGem measures light performance directly, whatever way the stone is cut. ImaGem does not predict from a huge number of potential flawed variables, but simply measure what is taking place with light in the stone on the machine at that time.

The AGS and GIA approaches will be very good for cutters to be able to program their machines and human cutters toward making high quality diamonds, but there are many, many variables. As cutters learn more, they will again, find out how to somewhat cheat the system wherever GIA or AGS has a weak spot in their measurements or calculations. The weakness in the Sarin measurements themselves lead to potential problems with predictive accuracy. With ImaGem, there is no prediction of light from ray tracing formulas derived from physical measurements of the diamond. Instead, it will be a measurement of the actual light behavior that exists in that diamond, not in diamonds somewhat like it.

The symmetry measures taken with ImaGem are also totally automated. Table parallel to girdle, table facet length uniformity, crown and pavilion angle matching, centering of the culet, uniformity of the outline, centering of the table, table or girdle tilt, side to side and end to end matching in fancy shapes, radius comparison of curved sides, and more are automatically checked and reported on in the complete diamond reports. However, symmetry is not a determining factor of light behavior, but a part of cut craftsmanship quality. Both elements are important.

For engineer types, the more parameters the better. For cutters, the parameters will definitely give them goals for cutting large amounts into generally fine cut material. For perfectionists and retail consumers, it is my opinion, that direct measurement of the light itself will be the very best way to know that particular diamond with any and all variables taken automatically into account. I'll never be the AGS or the GIA, but I have fortunately latched onto something that I feel will be even better. Time will tell and I await the contest of methodologies.
 

Maxine

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How will AGS and GIA make their determinations????
 

niceice

Brilliant_Rock
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Date: 5/25/2005 12:23:12 PM
Author: JD_MD

So a stone that currently grades as an AGS 0 that has excellent facet structure per the Sarin report, an HCA score less than 2 and scores well on the Brilliance Scope should make the ''cut'' under the new AGS scoring system? Or should one consider waiting for the new AGS standards? It would suck to realize my new 2.25 ct AGS 0 diamond is now an AGS 1 (and worth potentially 10-15% less). Maybe I should wait to purchase?
Actually diamonds that were graded by the AGS after October 1, 2004 were already evaluated using the new standard while at the same time being evaluated using the old standard... Thus you can verify whether a diamond graded by the AGS prior to the official release of their new grading system on June 1st will qualify as "ideal cut" on the new standard if it was graded after October 1, 2004. We do it all the time. Do you think we''d stop our business for this?
 
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