GIA EX cut = Ideal cut?

[macchio123]

Hi Everyone,

Is GIA''s excellent cut the same as an ideal cut?

Thanks!

 

[stone-cold11]

No. Ideal cut grade is issued by AGS.

If you are asking if GIA Ex grade will perform well, not necessary as GIA Ex allows for proportion that will allow for light leakage out the pavilion of the stone.

Use the cut adviser to weed out these proportions.
https://www.pricescope.com/cutadviser.asp

 

[Todd Gray]

As Stone Cold indicated, only the AGS Laboratory can determine whether a diamond is "ideal cut" because the term is part of their grading system... Of course, the AGS Laboratory was not the first member of the industry to use the term "ideal cut" to describe a diamond, in G.G., Al Gilbertson's book "American Cut - the First 100 Years" this is stated about Frank Wade, a member of the GIA advisory board in 1947:

"Wade's influence on the trade's understanding of diamond cutting quality was far reaching. An early advocate of the American Cut round brilliant, he later equated it with Tolkowsky's calculations and was one of the first leaders in the trade to call it an "Ideal Cut." (circa 1947, page 9

Herein we have the dilemma of terminology... And I think that a diamond with proportions determined to be within the context of the range defined by the AGS Laboratory as "Ideal" which is graded by the GIA as having Excellent polish and symmetry may arguably be referred to as "an ideal cut diamond" by the trade.

However, it might (partially) be for this very reason that the AGS Laboratory introduced an additional Light Performance rating to their grading system on June 01, 2005 and this is something not currently addressed by the GIA grading system! And there is no way of accurately assessing whether a diamond graded by the GIA, with proportions within that specified for the AGS Ideal 0 proportions rating, with GIA Excellent polish and symmetry, would actually be graded as AGS Ideal 0 for Light Performance because only the AGS Laboratory has the platform to make that determination...

So I guess the most accurate answer to "GIA Ex cut = Ideal cut?" is, uh, maybe, but maybe not

 

[yssie]

Date: 5/4/2010 1:16:59 PM
Author: Todd Gray
As Stone Cold indicated, only the AGS Laboratory can determine whether a diamond is ''ideal cut'' because the term is part of their grading system... Of course, the AGS Laboratory was not the first member of the industry to use the term ''ideal cut'' to describe a diamond, in G.G., Al Gilbertson''s book ''American Cut - the First 100 Years'' this is stated about Frank Wade, a member of the GIA advisory board in 1947:

''Wade''s influence on the trade''s understanding of diamond cutting quality was far reaching. An early advocate of the American Cut round brilliant, he later equated it with Tolkowsky''s calculations and was one of the first leaders in the trade to call it an ''Ideal Cut.'' (circa 1947, page 9

Herein we have the dilemma of terminology... And I think that a diamond with proportions determined to be within the context of the range defined by the AGS Laboratory as ''Ideal'' which is graded by the GIA as having Excellent polish and symmetry may arguably be referred to as ''an ideal cut diamond'' by the trade.

However, it might (partially) be for this very reason that the AGS Laboratory introduced an additional Light Performance rating to their grading system on June 01, 2005 and this is something not currently addressed by the GIA grading system! And there is no way of accurately assessing whether a diamond graded by the GIA, with proportions within that specified for the AGS Ideal 0 proportions rating, with GIA Excellent polish and symmetry, would actually be graded as AGS Ideal 0 for Light Performance because only the AGS Laboratory has the platform to make that determination...

So I guess the most accurate answer to ''GIA Ex cut = Ideal cut?'' is, uh, maybe, but maybe not

I think I just snorted into my tea.

Basically - it''s as Todd states, it depends who is calling it "ideal". If the AGS report is calling it "ideal cut" then it''s an AGS0, that lab''s highest cut grade. If a salesperson is calling it "ideal cut" you''d best inquire into exactly what metrics he or she is using. GIA "Ex cut" is not the same as AGS0 - the two labs have different specifications for their top cut grade, though there is significant overlap.


Proportion charts:
GIA: http://www.gia.edu/diamondcut/06_estimating_a_cut_grade.html#lookup
AGS: http://agslab.com/trade_research_and_development_proportion_based_cut_grade.php

 

[Lorelei]

Date: 5/4/2010 1:16:59 PM
Author: Todd Gray
As Stone Cold indicated, only the AGS Laboratory can determine whether a diamond is ''ideal cut'' because the term is part of their grading system... Of course, the AGS Laboratory was not the first member of the industry to use the term ''ideal cut'' to describe a diamond, in G.G., Al Gilbertson''s book ''American Cut - the First 100 Years'' this is stated about Frank Wade, a member of the GIA advisory board in 1947:

''Wade''s influence on the trade''s understanding of diamond cutting quality was far reaching. An early advocate of the American Cut round brilliant, he later equated it with Tolkowsky''s calculations and was one of the first leaders in the trade to call it an ''Ideal Cut.'' (circa 1947, page 9

Herein we have the dilemma of terminology... And I think that a diamond with proportions determined to be within the context of the range defined by the AGS Laboratory as ''Ideal'' which is graded by the GIA as having Excellent polish and symmetry may arguably be referred to as ''an ideal cut diamond'' by the trade.

However, it might (partially) be for this very reason that the AGS Laboratory introduced an additional Light Performance rating to their grading system on June 01, 2005 and this is something not currently addressed by the GIA grading system! And there is no way of accurately assessing whether a diamond graded by the GIA, with proportions within that specified for the AGS Ideal 0 proportions rating, with GIA Excellent polish and symmetry, would actually be graded as AGS Ideal 0 for Light Performance because only the AGS Laboratory has the platform to make that determination...

So I guess the most accurate answer to ''GIA Ex cut = Ideal cut?'' is, uh, maybe, but maybe not

Great explanation Todd!

 

[oldminer]

Not that I necessarily agree totally with the following, but I belive that I couild make a very good case for a GIA EX cut being called "Ideal Cut" by a seller if they were taken to task by a jealous competitor. As an independent expert, there is a lot of wiggle room for what is ideally cut? AGS does NOT have a trademark exclusivity on the term "Ideal Cut" and others can use it in ways that they wish to promote. Many GIA EX cuts could be AGS0 cuts and we know some are not. However, they are not a long distance away in visual beauty, durabiliity or other important attribute. Some people might prefer a particular non-AGS0 which was GIA EX and just not quite at the AGS standard.

In truth, the AGS standard is certainly valid in the overall, but it is the opinion of a profit oriented, highly competent laboratory which is making their main business and profits based on their marketing of the term AGS000. Profit is not inmmoral or unethical. Profits and marketing is okay with me, but it is a limited point of view and not all encompassing. To disqualify a diamond from a search for a great stone because it is not AGS0 and "only" a GIA EX is a mistake for most consumers although anyone who buys an AGS0 will surely find the cut and beauty highly attractive. They likely would find the GIA EX stone very much the same as the AGS0 in appearance until a very careful analysis or set of images were produced to show what nuance differences are present. There might be no differences on occasion, but usually there is some difference that can be pinpointed.

I would encourage those who shop for AGS0 stones to include AGS1 and AGS2 stones in their search. Some of those are going to look great, too and have no premium attached. Of course, such stones graded at that level are rare because most of the stones which are near misses to AGS0 end up with GIA EX anyway..... I think AGSL needs to find a better way to market their AGS1 and AGS2 grades to give them a broader market share. I'm sure they could hold up their end of working in such a larger market position. It would be good for GIA to have a bigger competitor. It would lead to further innovation and even better lab products and services for both labs.

 

[Lorelei]

Date: 5/5/2010 9:39:43 AM
Author: oldminer
Not that I necessarily agree totally with the following, but I belive that I couild make a very good case for a GIA EX cut being called ''Ideal Cut'' by a seller if they were taken to task by a jealous competitor. As an independent expert, there is a lot of wiggle room for what is ideally cut? AGS does NOT have a trademark exclusivity on the term ''Ideal Cut'' and others can use it in ways that they wish to promote. Many GIA EX cuts could be AGS0 cuts and we know some are not. However, they are not a long distance away in visual beauty, durabiliity or other important attribute. Some people might prefer a particular non-AGS0 which was GIA EX and just not quite at the AGS standard.

In truth, the AGS standard is certainly valid in the overall, but it is the opinion of a profit oriented, highly competent laboratory which is making their main business and profits based on their marketing of the term AGS000. Profit is not inmmoral or unethical. Profits and marketing is okay with me, but it is a limited point of view and not all encompassing. To disqualify a diamond from a search for a great stone because it is not AGS0 and ''only'' a GIA EX is a mistake for most consumers although anyone who buys an AGS0 will surely find the cut and beauty highly attractive. They likely would find the GIA EX stone very much the same as the AGS0 in appearance until a very careful analysis or set of images were produced to show what nuance differences are present. There might be no differences on occasion, but usually there is some difference that can be pinpointed.

I would encourage those who shop for AGS0 stones to include AGS1 and AGS2 stones in their search. Some of those are going to look great, too and have no premium attached. Of course, such stones graded at that level are rare because most of the stones which are near misses to AGS0 end up with GIA EX anyway..... I think AGSL needs to find a bettr way to market their AGS1 and AGS2 grades to give them a broader market share. I''m sure they could hold up their end of working in such a larger market position. It would be good for GIA to have a bigger competitor. It would lead to further innovation and even better lab products and services for both labs.

I think thats a great point David and something for us to take on board, there can be some superb stones available in these grades.

 

[macchio123]

Thank you all for your responses! This site is great and full of expert opinions which were helpful in our purchase. I don''t have the GIA cert with me, but we wound up with an EX/EX/EX, 1.6 ct, E color, SI which was eye clean to us and to the jeweler. We were able to compare and contrast several loose diamonds before making the decision.

FYI, I mentioned to the jeweler about all of the input and research that I had gotten from PS. I was able to have a healthy Q&A with him regarding the diamonds we were shown, and talked about the various techniques mentioned on PS as input on our decision. Who would''ve thought that there was more to it that just the 4Cs that are advertised on some websites?? This has been a great learning experience, and I will highly recommend this site to all of my friends!!!