ideal cut.

[javadud2]

I need an honest opinion about a stone I am about to buy for an engagement ring.

from the GIA lab grade report:

carat size: 95 points
color: H
clarity: VS2
polish: very good
symmetry: very good

from the Megascope Report:

diameter: 6.43mm
total depth: 59.9% 3.85mm
crown angle: 33.2% (32.7% - 33.4%)
crown height: 13.4% (13.1 - 13.5) 0.86mm
pavil angle: 40.9 (40.7 - 41.2)
pavil depth: 43.3 (43.1 - 43.5) 2.78mm
culet: 0.4%
table: 59.6 (59.4 - 59. 3.83mm

girdle thicknes: 1.7% valley girdle thickness (1.5 - 1.9)
3.2% 0.21mm (bezel girdle thickness)

I have seen different charts where differents ranges are used to categorize the cut as ideal or excellent (for example AGS(0), Class 1, Class2 , American cut, tolkowsky, etc.).
Based on the proportions mentioned above, can I consider the diamond ideal, excellent? How do I know how much light will it return?, leak?
Any help will be appreciated, thanks in advance.

 

[valeria101]

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On 8/15/2004 1:32:54 AM javadud2 wrote:



How do I know how much light will it return?, leak?
----------------

You may want to take a look on the "Tools" pages linked to Pricescope's front. They describe three such tools. At least the Cut Adviser ( = "HCA") you could use with the numbers at hand. It is better to test the diamond for brilliance directly (and there are a few toold meant for that such as the 'Ideal Scope" mentioned among those tools and the Brilliancescope and Isee2 that I know of). Each have their followers and detractors, of course, but, as far as I know, these seem to single out a rather tight range of cut parameters as "great".

Again as far as I know, the numbers you posted fall outside the AGS0 range (table too big) but do fit the popular understanding of 'Tolkowsky' proportions (LINK) and, according to the respective Cut Adviser should yield quite a brilliant stone.

It seems that this is one of th elucky diamonds that do get good light return outside the "ideal" proportions (and premium) - it is close to those 60:60 (Link) proportions, but gets a lucky combination of crown and pavilion angles.

By the same theory that yielded the HCA and the comments on the 60:60 mentioned above, this stone may have less contrast (or scintillation, whatever that means) than one closer to the traditional ideal range (say AGS0 to cut it short) but the overall light return is still way up there

This is about all I could say

Hope it helps ...

 

[Regular Guy]

I agree with most everything Ana has said; with a 1.4 on the HCA scale (yes, I've become a true believer), your diamond is likely to perform very well. Further confirmation by the tools she mentions may be helpful. Since your eyes are a tool, too, you have to be the judge whether these additional ones are necessary for your decision.

But, do you get bragging rights? My own search for an attractive diamond a first and then a second time (after her diamond came out of her ring) led me to look for "ideal" cut diamonds, after seeing brilliant ones being called this. Using the language of "ideal" led me to this site, and some additional tools for identifying a beautiful diamond. I'm not sure whether or not it is "kosher" to call the diamond "ideal," if it doesn't conform to one cut grade or another. However, if it is understood that "the large part" of most present cut grades use systems for defining ideal by way of defining a set of tolerances, by which you can predict the good light reflecting qualities of the diamond, then -- at the very least -- HCA can be judged as yet another, if not better, ideal cut grading system (where those tolerance ranges are calculated more directly by the good score). In this case, by your score of between 0-2...you can call it as you like.

Seems like you have a very good find. Best of wishes. By the way, if you go forward (and, by the way, I write this with self-interest, having purchased a "non-ideal cut" diamond with a good HCA score), I hope you'll let us know what the appraiser marks, by way of the diamond's cut, and if you're satisfied with this (I had mine include in the report documentation of the HCA score, so we'll see).

 

[javadud2]

Thanks Ana & Ira for your responses. I got the stones today. I got 2 sidestones (0.25 carats each aprox., 0.53 tcw) with similar quality for a 3 stones engagement ring. I have an appointment with an independent appraiser this week. I will definitely post results after I get the appraisal.
In my opinion, I got a good deal for the stones and I am very satisfied with the brilliance and fire of the stones.
My uncle suggested that I should send the ring to GIA for a second lab grade report. Is this necessary? My uncle is somewhat paranoic and he is telling me stories about jewelers switching stones, yada, yada, yada. Should I listen to him? I can say that I trust the jeweler I bought the stones from and I will go back to him in the future. Anyway, your opinion and/or suggestions will be welcomed and appreciated.

 

[Regular Guy]

Javadud2,

Just my 2 cents... and sense from reading here a short while, that such a procedure (sending -- back -- to GIA for confirmation) is not routine, and I'd think, ordinarily, would not procedurally necessarily even solve a problem. Say the mail room guy at GIA (or would you go there?) does the switch after the diamond is confirmed. Where goes your guarantee?

Seems like to the extent you do have such a concern, your local independant appraiser is the person you should more readily look to for the guarantee you'd potentially be seeking. For example, after looking at the diamond, they can hand you the ring, and you can walk away with said ring in your hand. Also, two more things:

1) I think standardly GIA diamonds will be stamped with a number on the girdle, that will correspond with the cert you would posess. With a 20x loupe you can see the numbers yourself.
2) Even your VS2 will have an inclusion, probably visible with a loupe. Your appraiser can train you to see it, and so you can at least do a confirmation for yourself that the diamond he/she sees that conforms to the cert has those characteristics.

So, by methods 1 & 2 above, you can come to trust yourself when handing the diamond over to someone. I am warned by the appraiser that, regarding method #1, such numbers can be removed. Still, I would trust method #1 over #2 in any dispute with a jewler I too late found I didn't trust, since -- it would seem to me -- any argument you'd try to make about an inclusion you could or couldn't see would not be something for which a local cop would be willing to slap the handcuffs on a guy. This opinion, of course, is just my own. Nevertheless, in anticipating the need to hand over one's ring with some frequency to a jewler to do routine prong checking and tightening, such precautions seem normative to me.

Best wishes,

 

[javadud2]

Well, I bought the ring and I got it appraised. The appraiser looked at it, measured, compared with master set of stones for color, check fluorescence, etc. etc. He tought that the stone was between G - H but he was more inclined to H. When he was inspecting the stone for clarity he had to inspected several times because he tought that was a VVS(1 - 2). After I told him it was a VS1 he did not agree and he checked it again and again. He still thinks is better than VS1.

From the GIA report: Appraiser:
carat size: 96 points 96.5
color: H H
clarity: VS1 VS1 or better
polish: very good VG
symmetry: very good VG
fluorescence: none none

Before I told him how much I paid for the stone he gave me the Rapaport report price for a stone like that and the price he thinks I paid for it.

(0.90 - 0.99 carats) Rapaport price : $5500 per carat: $5280 (0.96 carats)
He said that normally a stone with that quality can be found at $4752 (10% off the rapaport price). The price I actually paid for the stone was $4500.