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Need "Ideal" Advice

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rockhound

Rough_Rock
Joined
Jan 13, 2002
Messages
3
I'm looking for a 2+ carat ideal cut stone. I've done some studying on cut quality, but have some questions:

1) What do you experts think of the idea that for the "ultimate" in ideal cut, not only should the average crown and pavilion angles fall within ideal specs, but each of the eight individual angles must be within ideal specs?

2) Would my eye see the difference (all else being equal) between a stone whose average crown and pavilion angles were ideal, but on an individual basis some of the angles fell outside ideal range, versus one where all eight angles were ideal?

3) If the answer to question 2 is yes, then why do the grading labs (and almost everyone else)look only at the averages?

4) One stone I'm considering has a sarin report showing table off-center by .3% and culet off-center .6%. I haven't seen any info out there on how the culet and or table being off center might affect the cut quality, and if it does, how much off-center is acceptable?

4) The Stones other attributes:

Carats 2.493
Diameter 8.76mm (8.72-8.78)
Depth 5.34mm 61.0%
Crown 35.0 15.3%
Pavil 40.9 42.9%
Table 4.90mm 56%
culet 0.7%
girdle 1.2 - 2.1, 1.4% faceted
GIA Certed
Polish ex
Symmetry ex
Clarity VS1
Color G
Price $24,750

Is the stone great or mediocre? Is the price okay?

Please help! Thanks!

Vicky Walker
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
14,929
it is fantastic!

The reason the numbers are alittle off is to do with the measuring technique of Sarin. The table is probably very slightly tilted and this makes the individual number differences exaggerated. There is probably no real difference at all.
Add the opposing pavilion angles together so you get 4 numbers. The real deviation in pavilion slopes is the difference in the addition of these numbers, and it is probably very very small.
Try it and let us know the answer.
 

rockhound

Rough_Rock
Joined
Jan 13, 2002
Messages
3
----------------
On 1/14/2002 5:50:14 AM

it is fantastic!

The reason the numbers are alittle off is to do with the measuring technique of Sarin. The table is probably very slightly tilted and this makes the individual number differences exaggerated. There is probably no real difference at all.
Add the opposing pavilion angles together so you get 4 numbers. The real deviation in pavilion slopes is the difference in the addition of these numbers, and it is probably very very small.
Try it and let us know the answer.
----------------

All the seller of the stone has shown me are the GIA certificate, and a Sarin report summary (averages). He doesn't have a Sarin machine or a megascope to measure the individual angles, which I would need to perform the test you are suggesting.

Most Sarin reports I've seen show averages only. However I have seen some that give all the angles like a megascope report does. If a Sarin has been run, wouldn't the person who did it have access to the full report?

If not, can the cutter request and obtain this info from the GIA, or could the seller (who's a certified gemologist) accurately take a manual measurement of the angles?

You didn't comment on my question about whether it was important to ascertain that all 8 crown and pavilion angles are within ideal range, or if the fact that just the averages are, means it's a well cut stone. (I'm really agonizing over this--don't want to make a mistake!)

The stone would qualify as an AGS ideal cut based on the averages. It seems to be a good value for the size, color, and clarity. I hate to pass it up--if variances in the individual angles would not make a significant (distinguishable to the human eye) difference in the appearance of the stone.

Please comment. Thanks!

Vicky Walker
 

Garry H (Cut Nut)

Super_Ideal_Rock
Trade
Joined
Aug 15, 2000
Messages
14,929
Vicky it has excellent symmetry.
it can not be far off.
It sounds beautiful, you have gotten to much into the numerical and seem to be loosing the purpose.
The paper is to describe the beauty of the stone, and the stone you refer to will be beautiful, so buy it before someone else does.
If you are concerned then as we always say - send it to Dave Atlas or another recommended appraiser for a second opinion and all the tests you caan imagine.
 

rockhound

Rough_Rock
Joined
Jan 13, 2002
Messages
3
Thanks so much for your advice. I bought the stone, and am very happy with it!

I did have the seller obtain a megascope analysis, and got all the info I wanted--you were correct--the variation between the lowest and highest crown measurements was just 0.4 degrees, and on the pavilions 0.3 degrees.

I also had the opportunity to view the stone with a gems fantasy scope and saw (though my eye is inexperienced and wasn't looking through a scope) perfect hearts and arrows!

Thanks again for your help.
 
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