AGA Cut Charts--Same cut or best cut?

[researcher]

Sorry if that subject header doesn''t make sense; it''s been a long day. Although I now have my e-ring, I am helping a friend with choosing hers and am still uncertain as to whether the charts are most predictive of ideal/premium cut stones if the specs are all in the same category (e.g., all 1B) or whether you''re better off getting a stone with an overall rating of say 1A. The reason I ask is there seems to be a relationship between the various angles, table and depth, and it therefore makes me wonder if it''s better to have a stone with specs that fall into the same cut grade. For instance, if you have a depth in the 1B range, is it better to have a table in the 1A range or the 1B range? What triggered this question was a website I read that stated cutters can make up for things like depth by cutting particular angles in the table and pavilion to make sure the light reflects appropriately. Am I making any sense? I don''t remember where I read the original article so I''m having trouble coming up with the right terminology, but I hope you''ll be able to figure out what I''m trying to get at. I''m basically trying to figure out whether it''s the combination of numbers that impacts the results of the cut more than getting an overall score that''s a little higher.

 

[researcher]

Is my question worded that poorly or do people just not have the answers?

 

[strmrdr]

oldminer and a couple others are likly the only ones qualified to answer the question.

I dont know is my answer... which isnt very helpful...

 

[pqcollectibles]

I cannot answer your question specifically, but I can add some general info.

Cutters are always working with the personality of the rough. Sometimes, the rough is not cooperative and they do compensate for a negative in one area with a complimentary positive to produce a beautiful diamond.

Johan from Melbourne Diamond Exchange wrote an interesting post a while back:


We recently where lucky enough to acquire a large (8+ct) rough diamond of exceptional color (D) and clarity (VVS2) with strong blue fluorescence. Unfortunately the diamond was an irregular shape(cleavage) with some graining forcing the cutting into a shallow pavilion angle. After much pondering and sleepless nights and a lot of help from Diamcalc the cutter came up with a set of dimensions that would seem bizarre to the promoters of the “sweet spot”

The end result was one of the liveliest and beautiful diamonds I have ever seen.

Indecently this diamond sold to the first person we showed it to. Maybe that was just a coincidence,

The numbers are.
Weight =3.57 ct
Recovery = 44.8% (not that good but ok for the shape)
Color = D
Clarity = VVS2
Total Height = 59.7%
Table = 57%
Crown Angle = 37 degrees (16.2%)
Pavilion Angle= 39.9 degrees (41.8%)
Girdle = Med – slightly thick
Culet = Very Small

Some food for thought

Johan

You can find more info on the diamond they cut in this thread:

https://www.pricescope.com/community/threads/hit-me-if-you-can.11944/

More specifics regarding Princess cuts will have to come from one of the pros, tho.

 

[oldminer]

I read and re-read your question. Truthfully, I can't make much sense out of it. I apologize.....The charts are geared to steer people into making the best set of compromises in cutting so that they still get a good looking, durable and good sized looking diamond. Having specs from different levels of the charts in one stone happens a lot. The more a diamond is in the higher grades, the morel likely it is well fashioned. Light behavior may not directly relate in every case to AGA Cut Class. There are odd ways of cutting a lower cut class diamond that may result in super brilliancy. However, do these strange stones look "right"? Are they durable? Are they going to be popular? I don't have those answers.

My conservative view is that traditional cutting strategies will be those that remain popular while only a few new models will have any degree of future success. If a diamond is a 1A to 2A cut stone, I anticipate it will always be among the better looking diamonds with a good combination of features and light behavior characteristics. Of course, this depends on the good sense and judgment of the diamond cutter. An idiot can ruin even a good potential stone. Idiot cutters are quite scarce as one thing diamond merchants have no patience with is a stupid or ill trained cutter. Someone like that costs a business way too much money.

 

[researcher]

Thanks everyone for your responses! Now that I've slept some, let me see if I can clarify. When choosing a stone, is it better to have a stone with an overall cut score of, for instance, 1B (with say depth 2A and table 1A), or a stone that gets an overall rating of 2A but has the depth, table, etc. all in the 2A category. As pqcollectibles post suggests, cutters have to work with the rough they're given (and try to retain the most weight for retail purposes). So, my question is whether a better cut stone (princess let's say) would be one with, for instance, a depth of 75.5 (2B) and a table of 68 (1A) or a depth of 75.5 (2B) and a table of 74.1 (2B). Am I making more sense? My guess would be staying within the same category would be more likely to produce crown and pavilion angles that compliment each other better, and lead to a more beautiful stone. Am I wrong?

 

[oldminer]

You need a consistent way to make the judgments you are asking for. For that specific reason my AGA website automates this process utilizing my rules in an objective manner to give you the correct result. Now, I may have something wrong with my methodology and the answer is based on my best present beliefs. Some experts might slightly disagree, but that is to be expected. I have always welcomed constructive advice and have made some small changes over time to improve the result.

The biggest help in choosing a diamond is to use the charts in a way to eliminate dogs and find better possible stones from which to select. Then you use your brain and your eyes to choose one that is the best for YOU... We may have better tools shortly to help you, but I hope we never get to the point where beauty is not subjective. The subjective nature of judging what pleases us most is a great gift and a wonderful freedom that no one would want eliminated...Certainly not me.

 

[researcher]

Thanks, Dave!
I was just curious. The stone I decided on was all (or almost all) in the 1A category, and it came out a triple VH on the Bscope! So all your work really paid off in my case

I was just curious about the best way to use the charts because my friend is trying to decide which stones to call in and wanted to narrow them down a bit more.