why should table be smaller than depth?
- Thread starter cryckman
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cryckman,
If you find out the answer let me know. I''ve got gorgeous princess cuts in my office, many with depths equal to or slightly below the table. Not sure where this idea that table less than depth is good started. My guess, however, would be that princess cuts with smaller tables typically will have a greater crown height. Also, as total depth increases, crown height percentage will generally increase. Thus if you have a stone with a higher depth and smaller table you theoretically could get higher crown percentages.
If you find out the answer let me know. I''ve got gorgeous princess cuts in my office, many with depths equal to or slightly below the table. Not sure where this idea that table less than depth is good started. My guess, however, would be that princess cuts with smaller tables typically will have a greater crown height. Also, as total depth increases, crown height percentage will generally increase. Thus if you have a stone with a higher depth and smaller table you theoretically could get higher crown percentages.
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I am responsible for starting this and for very good reason.
First let me emphatically state that this is NOT a hard fast rule and never have I said it was. There are princess cuts out there with tables >= total depth that exhibit excellent optics. I''ve tested quite a few stones that demonstrate this. HOWEVER ... when we''re helping clients and searching for diamonds by the limited numberes provided on lab reports we can''t afford to waste our time or the clients dollars calling in stones that are potential losers and we stand a much greater chance at finding an optically superior stone whose table is less than the total depth than the opposite. Ie. if I call in 25 princess cuts and the table is greater than the total depth maybe... MAYBE 1 or 2 will have acceptable optics. Reverse the table/total depth combo and we increase our chances GREATLY.
At the same token I would be quick to point out that just because a princess cut has a table that is less than the total depth IS NO GUARANTEE of excellent optics either.
The most critical relationship is that between the crown and pavilion angles and as AGS has recently confirmed and pointed out there are 2 sets of crown angles to be considered and 2 sets of pavilion angles to be considered *at a minimum*. That''s if you''re strictly going by the numbers. If I were about to drop thousands of my hard earned dollars I would want an optical analysis for light performance.
If you have any further questions feel free to ask.
Regards,
First let me emphatically state that this is NOT a hard fast rule and never have I said it was. There are princess cuts out there with tables >= total depth that exhibit excellent optics. I''ve tested quite a few stones that demonstrate this. HOWEVER ... when we''re helping clients and searching for diamonds by the limited numberes provided on lab reports we can''t afford to waste our time or the clients dollars calling in stones that are potential losers and we stand a much greater chance at finding an optically superior stone whose table is less than the total depth than the opposite. Ie. if I call in 25 princess cuts and the table is greater than the total depth maybe... MAYBE 1 or 2 will have acceptable optics. Reverse the table/total depth combo and we increase our chances GREATLY.
At the same token I would be quick to point out that just because a princess cut has a table that is less than the total depth IS NO GUARANTEE of excellent optics either.
The most critical relationship is that between the crown and pavilion angles and as AGS has recently confirmed and pointed out there are 2 sets of crown angles to be considered and 2 sets of pavilion angles to be considered *at a minimum*. That''s if you''re strictly going by the numbers. If I were about to drop thousands of my hard earned dollars I would want an optical analysis for light performance.
If you have any further questions feel free to ask.
Regards,
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researcher
Ideal_Rock
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From my experience, if the table is less than OR equal to (or at least close to the depth) the stones do tend to perform better. I don''t know if it''s because of the often greater crown or the relationship between the crown and pavilion angles, but I tested Rhino''s theory on over 45 stones and found he was correct-stones with tables smaller than the depth did tend to have more fire (a result of the crown) and leak less light. There are definitely exceptions to the rule, but as Rhino stated, do you really want to waste your time searching through the exceptions to find a good stone?
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This thread makes great refference... but you are talking of.... a tenth of a % ???
Forget that. You may want to look up some recent therads that ask about the differences between different measures taken of the same diamond. Those come within way more than 0.1% of each other, so the difference you are talking about cannot be distinguished from measurement error.
Judging from this, one can say that this stone has depth and table of about the same desirable number: the stone is definitely not deep at 65% and that table cannot be called either too small or too big. But then, once can only with for a picture and Ideal Scope. Not to mention the other numbers on the cert
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