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Ideal Princess Proportions

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Rhino

Ideal_Rock
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Today we ran across a princess cut with numbers to die for yet it's optical results were not as ideal as I thought. It makes for a good learning stone and a lesson in the ongoing study of princess cuts and the IMPORTANCE of the crown/pavilion relationship.

Rhino
 

Rhino

Ideal_Rock
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The thing that intrigued me about this stone is it's seemingly perfect proportions yet less than perfect BrillianceScope results and light return.

Sarin results reveal a 71.7% depth, 66.5 table, 10.6% crown height and a 56.8% pavilion depth. All the ingredients for a superstar princess cut. Below are Diamension and Diavision
files with 3d models.




Here is the actual LightScope image of the stone.

LightScope reveals nice dark reds in the center however pale reds
and white are predominant at the top and bottom halfs of the stone.



Here are the BrillianceScope results.



Now take a look at this princess cut with similar proportions.

This is a .92ct E VVS1 we have on our site.

Sarin results on this stone reveal a 70.9% total depth %, 64.8% table, 10.5% crown height and a 57.6% pavilion depth. Very similar to the 1.04ct listed above.





Here is the Lightscope image of this .92ct.

Drastically different as we now have the presence of more dark reds and blacks
(indicative of more intense light return) and while there are some areas of leakage by the corners, leakage is reduced.



Here are the BrillianceScope results of this diamond.



2 measurements I've left out of the proportions on these 2 stones are the crown/pavilion angle combo and THIS is where the difference lies between the above 2 diamonds. A side by side comparison of the numbers reveals everything pretty similar except for one factor. The pavilion angles on the 1.04ct are shallower than the .92ct which teaches us once again the important
relationship between crown and pavilion angles even in fancies such as the princess.

Measurements .92ct E VVS1 1.04ct D IF
Total Depth% 70.9% 71.7%
Table 64.8% 66.5%
Crown Height 10.5% 10.6%
Crown Angle 35.3° 35.5°
Pavilion Depth 57.6% 56.8%
Pavilion Angle 57.9° 54.2°


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jake88

Rough_Rock
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Apr 2, 2003
Messages
33
Rhino

I found a princess diamond with the following dimentions:

Carat Weight 0.5 carats
Shape Princess
Color E
Clarity VVS2
Depth 68.8%
Table 63%
Girdle THIN
Culet NONE
Polish GOOD
Symmetry GOOD
Fluorescence NONE
Measurements 4.74*4.42*3.04 mm

What do you think? are these good ones?
 

Rhino

Ideal_Rock
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WOW ... Leonid ... this is super cool. I see the link to the web page teaching posted the teaching here. I think that is excellent.

Jake, the lesson to be learned from the above 2 examples is that the difference in pavilion angles can make or break the stone optically even when the numbers look good. I am very anal about what I lay out my money for.

One reason why Rich and myself will not comment on what you got is because the information you give is extremely limited. There's absolutely no way for anyone here (even the most educated of us) to comment on your diamond with any accuracy.

The critical information of crown height, crown angles, pavilion depth and pavilion angles are missing from your info. Anyone to try to intelligently comment without that info is merely taking a shot in the dark in relation to how brilliant or fiery that stone is.

The info we CAN tell you about it is that it's not cut too deep (at68.
and the table looks like where it should be but that is ONLY a starting point and by no means enough info to make a educated judgement.

If you get the more critical info perhaps we can be of better assistance to you.

Peace,
Jonathan
 

Rhino

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btw ... To view the Sarin files on the above stones (and those with DiamCalc can import the file into their programs for analysis) you'll need the free Web Viewer download at this link. You can also export the file to a .gem file for all to view too.

http://www.sarin.com/viewer/SarinWebViewer.exe

Peace,
Rhino
 

jake88

Rough_Rock
Joined
Apr 2, 2003
Messages
33
Rhino

Thanks for the reply. I am just starting out with this stuff. I have the GIA papers, but it doesn't provide the information you mentioned. I guess I'll have to get it appraised?

Thanks
 

Rhino

Ideal_Rock
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Definetely. At least get a Sarin done if not an optical analysis to compliment it.

Peace,
Rhino
 

jake88

Rough_Rock
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Apr 2, 2003
Messages
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Definetely. At least get a Sarin done if not an optical analysis to compliment it.

Peace,
Rhino


Rhino, I'm getting the stone appraised on monday, however, I don't know what a "Sarin" is, is there a web site you can direct me to so that I can read up on it? Thanks
 

Garry H (Cut Nut)

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Aug 15, 2000
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As I have said before guys - proportions are no benefit with fancy shapes - too many variables acting in concert. There will never be a fancy cut HCA


This is why AGS have decided to move toward direct analysis.

Anyone know if AGS are going to make any big announcements at Vegas? They have been teamed up with 8* for 1 1/2 years now.
 

Garry H (Cut Nut)

Super_Ideal_Rock
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Aug 15, 2000
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1 more thing.

I have yet to see a princess that pleased me (except for fancy colors).

When I look with the ideal-scope I see diamonds with great light return - about 2-3 in 100, and 10-20 with better results, but they still leave me cold when I look with my eye.

The thing they miss out on is scintillation. I want more contrast in my diamonds and so many just look like crushed glass with not enough black through the ideal-scope.
 

Hest88

Ideal_Rock
Joined
Jan 22, 2003
Messages
4,357
Jonathan and all, this is fascinating information, and just proves, once again, what everyone has been saying about fancy shapes all along.

Garry, I hear you about princesses, but I think when it comes to fancy shapes the main preference is never due to the light performance, but always due to the shape. I'm partial to squarish shapes myself and doubt I'd ever buy a RB even if it's so sparkly I'd get a migraine looking at it.
 

barry

Shiny_Rock
Joined
Mar 21, 2001
Messages
441
Garry;

You're correct. But slowly the tide is changing and Princess'
are being cut with excellent scintillation and minimal light leakage.

Barry
www.superbcert.com
 
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