Cut 1A vs 2A (Round)

[esp102]

A few quick questions...1.) If a 1A cut is an AGS 0 cut - what would a 2A be?2.) If I find a diamond listed as 7.69 - 7.72 and find another diamond listed as 7.76 - 7.79 would the extra diameter be noticable and worth the extra money?At what measurement do you start to notice a change in size?3.) What is the prices difference for a 1A diamond and a 2A diamond? 5%, 10%, 15%...Thanks!

 

[pricescope]

Hi esp102,
1.) If a 1A cut is an AGS 0 cut - what would a 2A be?I tried to put comparison tables below. As you can see, 1A is more strict than AGS0 i.e, average 1A stone is more close to Tolkowsky than AGS0________________/ AGS 0 / 1A
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Table Diameter: / 52.4 - 57.5% / 53-58%
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Crown Angle: / 33.7 - 35.8° / 34.3-34.7°
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Pavilion %: / 42.2 - 43.8% / 42.8-43.2%
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Girdle Thickness:/ Thin, Medium, Slightly Thick / MediumAs for 2A, difficult to say - they overlap

________________/ AGS 1 / AGS 2 / AGS 3 / 2A
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Table Diameter: / 51.4-59.5% / 59.6-61.5% / 50.4-63.5% / 51.5-63%
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Crown Angle: / 32.7-36.3° / 32.2-36.8° / 31.7-37.3° / 33.9-35.8°
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Pavilion %: / 43.9-44.3% / 41.7-44.8% / 41.7-4.8% / 42.4-44.0%
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Girdle Thickness: / Very Thin / Vr Thin to Sl Thick / Thick / thin to sl. thick
----------------------------------------2.) If I find a diamond listed as 7.69 - 7.72 and find another diamond listed as 7.76 - 7.79 would the extra diameter be noticable and worth the extra money?I guess larger diameter (spread) at the same weight should be beneficial but you have to consider other factors too: girdle, crown and pavilion angles, etc. You might want to check the Cut Adviser to analyse the stones on overall visual performance: www.pricescope.com/cutadviser.asp 3.) What is the prices difference for a 1A diamond and a 2A diamond? 5%, 10%, 15%...Check price stats for different cut grades on this site: www.pricescope.com/repscope.asp Hope it helps

 

[bacon]

Cut class 1A and 1B are both Ideal cuts. 1B includes the lessor performers of the Ideal range.

 

[oldminer]

Joe, Thanks for the nice comparison chart of OUR AGA/NAJA cut grades to AGS.You will find that an AGS 0 may be still deeper than the 62.99% total depth of our 1B parameter. I know it is a game for diamond cutters to save weight and still get the "0" grade. It is just a similar game for cinsumers to be aware of it and opt for the best make stones that are really cut right.------------------
David Atlas
Accredited Gem Appraisers

 

[pricescope]

Thank you Joe, I know you prefer AGA system to AGS. Me too since it has gradings for fancies too.Oldminer, thanks for posting! Great to see you back!

 

[bacon]

Dave-I use the AGA/NAJA system because it gives me the most accurate judge of cut available to me today.thanks for posting it. There is no way to know how many consumers you have helped by your website.

 

[VampireX02]

This is from a really old thread...but I just have a simple question....

My stone checks out as a 1A when I had it appraised at AGA. But yet, the HCA gives it a rating of 1.6, which would seem to be low for a 1A (since it's a more "strict" cut than AGS0).

Is that because the 1A is very close to TIC, and HCA rates TIC at around 1.5? Is that correct?

Also, typically, stones that rate let's say around .5 on the HCA....can they ever be in lower AGA classes like 1B or 2A? Or even lower AGS classes like a very good cut?

 

[oldminer]

I believe you wil find the highest rated HCA stones within my AGA 1B category and possibly also in the best of the 2A category. It depends on what is "wrong" or "right" with the diamond. Certain "faults" create brilliancy, but stray away from the Tolkowsky approach to an ideal mix of brilliancy, scintillation and dispersion.

To judge a diamond, no one has yet to come up with a foolproof way to know exactly what is happening without seeing the indicidual stone.

Many AGS 0 stones have depth problems and are not the very best cut. The AGA 1A is a very narrow range and while all the stones look excellent, they maay not perform according to the HCA in exact harmony.

I personally bought a large AGA 2A round for my wife a couple years ago which is a super looking diamond. Everyone loves the way it looks and sparkles. I bought it by looking at the stone and then measured the cut grade.... I know you can't do that, but the cut grading helps assist consumers to do a better job.