Confused over grading information

[solange]

I have already purchased a stone based on information I got from Pricescope contributors and tutorials. I am very pleased with my purchase but some of the new information coming out is very confusing.

With the revised chart from Dave Atlas, good polish and symmetry are now in the 1A category and there have been comments made by some that excellent polish and symmetry are not major factors. However when buying a GIA graded stone there is a premium on stones with excellent polish and symmetry. Since the GIA does not provide other pertinent information about the cut quality, are people overpaying for excellent polish and symmetry?

In the case of my stone which is graded good polish and very good symmetry by the GIA, when I posted the Idealscope, Garry H commented that the symmetry was not very good because the upper facets were not well aligned with the lower but that "it is an example of a type of symmetry defect that can improve a diamond's appearance."
Dave Atlas recently made a similar though less specific comment concerning symmetry.

I have tried to get additional information here on symmetry and the role it plays because I am now wondering if too much emphasis is being placed on symmetry and polish. I am not talking about those looking for absolute top quality and precision cut. I am addressing an area where it may be possible to compromise on those two areas and get a larger or better color stone. Stones similar to mine seemed to have a higher price if they had excellent symmetry and polish on the GIA grading.

I hope someone is willing to address the area of symmetry and be specific as to how one would know how to determine the effect of symmetry on the appearance of a stone.

 

[Garry H (Cut Nut)]

You will be sorry after you read this lot

Symmetry and science

 

[Garry H (Cut Nut)]

Solange I recieved a PM from you.

My meaning is you will be sorry you asked for more information, not that you would be sorry about your purchase.

If you read the information on that website you will see that what GIA put on a report about symmetry may or may notrelativity to a diamonds appearance (eg the explanation of the stone with H&A's and GIA good symmetry).

So relax.
Infact if you have a large stone and if the top and bottom facets were not aligned perfeclty (for example) then your stone will appear to have more facets, which means you will see a larger number of flashes, which is better for you in a bigger stone unless you wish to show off to your neighbours (where bigger flashes may be more likely to be seen from greater distances).

 

[solange]

Dear Garry,
Thank you for your prompt response and for putting my mind at ease. I misunderstood your message to mean that I would be sorry I bought this stone. I had looked at diamonds in the Diamond District for several months before I found Pricescope. It took about four months to find this stone through a Pricescope vendor.

It was a major decision to make such an expensive purchase on the Internet and I thought I had covered every angle. The Sarin, OGI and AGS indicated an Ideal cut and the Holloway Cut Advisor came up with a low score with all excellents.

Then when I misread your message I thought I had overlooked an important factor--that the upper and lower facets were not well aligned and that this was a serious defect. The stone is 4.10 and it does look like it has a lot of small facets as you indicate.

I appreciate the time you took to respond. I reread the article on the link and realize that what you are saying is that there is a difference between a GIA symmetry grade and the extensive internal symmetry grading you describe.

I wondered why my stone appeared to have a lot of small facets and I am very happy with the look. In my case, this symmetry "defect" worked out well and I am very grateful for the information you provided.