How do Table/Depth numbers affect how big a princess cut looks?

[AZDiamondShopper]

Hi,
I have been reading on this forum for quite some time. I know that numbers don''t tell the whole story on princess cut diamonds. However, can anyone tell me how the numbers can influence how big a princess cut looks to the eye? I have seen various princess cuts with very good Bscope results, but they vary widely in table and depth percentages. I want to get a princess cut with great Bscope results, but I also would like to know how the numbers affect the visual size appearance of the diamond.
Thanks as always!

 

[mdx]

Most princess cuts are cut from Octahedrons (They look like two pyramids on top of each other joined at the bases.) and can yield up to 80% recovery from the rough, This is why you will find most princess cuts are very deep (heavy) and with large tables 75% –80%.

The large tables are usually at the expense of crown height thus reducing visual performance. The larger tables do to some extent give the elusion of a bigger stone but at the expense of beauty

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As a simple guideline you, the shallower the depth the larger the visible surface area The smaller the table the better the diamond will look.

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My personal favorite is a depth of 65% and a table of 65% with a crown height of around 10%. But they are not easy to find.

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I would suggest that you use the cut charts of Dave Atlas at www.gemappraisers.com as a guideline.

/www.pricescope.com/idealbb/images/smilies/3.gif[/img]>/www.pricescope.com/idealbb/images/smilies/3.gif[/img]>

Wayne

Melbourne Diamond Exchange ltd (Australia)

 

[AZDiamondShopper]

Thanks for the reply. Anyone else?

 

[Giangi]

Stick with a princess w/57-68% table and ~65% depth... Crown higher than 10%... No extremely thin or very thin girdles...

 

[Rhino]

My personal experience with princess cuts of those numbers are not that good. Especially with stones where the total depth is 65% and the table is 65-68%. The reason I say this is because if the stone has a total depth of 65% with a 10% crown, you usually have a 3% girdle which leaves a pavilion depth of approx. 50-52% and THAT pavilion is generally too shallow for the 10% crown that it is being coupled to which generally results in too much leakage. I appreciate the attempts at princess cut grading scales but a scale that does not consider the crown/pavilion relationship IMO is useless. I am excited about the upcoming grading scales AGS will be producing which will be based on the optical quality of the stones and not necessarily the numbers.

My .02c

Rhino

 

[AZDiamondShopper]

Rhino,
When will these new grading scales be available?

 

[AZDiamondShopper]

Anyone else aware of this?

 

[oldminer]

I know what Rhino is talking about and agree that the relationship of certain elements needs to be correct. Looking at separate components of cut may only give a clue as to the end result. I have seen many AGA 1 grade princess cuts that cutters made into excellent and brilliant diamonds. I have seen a few, maybe more than a few, that had a bunch of "correct" parameters, but failed to be pretty or really brilliant.

I, too, await the coming of light return analysis as a key ingredient to grading the best cut and most attractive diamonds.

One thing is certain. A diamond that is overly deep does not show a reasonable amount of size (diameter) for its weight. If you pay for a 1 ct diamoind, it should look like a 1 carat stone, not a 3/4 ct stone... That isn't science, but just common sense.