Emerald Question

[EdiL]

I've been shopping for two stones for a pair of earrings for a few weeks now, and have been learning all I can about cut. I am making Atlas 2A measurements my starting point, but I've found some conflicting information. I found another site with a very large tutorial stating that, "the proper depth percentage for an emerald cut is between 65 and 75%. An emerald cut shallower than 65% will let a greater percentage of light leak through he pavilion." This contradicts the Atlas rules of 60 to 65%. I would appreciate any expert's opinion. I would love to have numbers for the "Ideal Emerald Diamond." As well, it seems to me that somewhere along the line someone in the industry could have hired a physicist and mathematician to find out the precise definition of "perfect" cut in "fancy" shapes, given the fact that light reflection and refraction through crystallized carbon are quantifiably measurable. Perhaps that kind of accuracy would lessen the "mystique" of diamonds? The other thing I've noticed is that the stones available on the web tend to have "good" to "very good" symmetry. I have yet to see any "excellent" stones listed. Why is that?
Thank you all for any input.
Edward di L

 

[pricescope]

Hi Edil,I think AGA grades are the best guidelines available today. AGS is working on the grades for fancies but they won’t be ready earlier than year or two.There is an opinion that fancies should be seen and compared to each other. It is much harder to predict their look based on numbers than for rounds. Fancies are very much upon personal taste.A bit shallow depth can be beneficial since the diamond will look larger for its weight.Symmetry. I guess since there is no "ideal" cut defined for the fancies cutters are not trying to get excellent grade for the symmetry.Leonid

 

[oldminer]

The AGA Cut Classes were made from observing many stones over a long period of time. So very few are cut the same and so many are cut to save weight, I really had to hypothecate what the 2A grades in emerald, rediant and princess cut should be. I tried to keep in mind the parameters that looked best and wanted at least some small number of stones to qualify for the grade. It is a wide range of parameters that I am not able to tighten up further visually. We all await more scientific study such as AGS. At some point cutters will make efforts to cut some diamonds to the 2A standards and we will see a geater number available. It amazes me that with the market nearly pre-sold on these shapes, that so few are around... No one wants to be first I guess.------------------
David Atlas
Accredited Gem Appraisers

 

[oldminer]

You will find other opinions about what is "best" from sellers of diamonds than my own opinions that are based from my observation, but not motivated by the stones most readily available to sell to you.I hope you can discern the meaning of the above.I think objective gemologists basically agree with my AGA Cut CLass parameters, but there is scientific study going on now that will eventually give a more precise set of answers. Since each lab fights over urf on these issues, no one accepts anyone else's opinions readily. AGS has gone off to investigate. Maybe they will someday have some better results for all of us, maybe not.------------------
David Atlas
Accredited Gem Appraisers