Dullness in a Princess

[taddles]

I''ve been looking at a few princess cuts that local jewelers have shipped in for me. In all of them I found a sort of dull or vacant spot when looking at the center of the stone. Almost appears as a black-greyish area when looking at the stone.

Is this a characteristic of the princess cut in general? Or will an Ideal or Premium cut princess eliminate this?

 

[Nicrez]

NOOOO!! Princess cuts with a huge table can have such a sink hole of refraction. I believe these stones are cut for size and not for sparkle. if the depth is too low, the light entering the stone can not refract and reflect properly, so there is that sparkle-less zone you are seeing...

Try to follow guidelines for a stone with a smaller table % than it's depth, and may bother numbers be under 73%, that could work out very well, with less dullness.

It's sad that SO many cutters cut so badly, because if you are spending thousands of dollars on a luxury item, it might as well do what it's supposed to and sparkle!

 

[moremoremore]

I do want to add that it dawned on me to do a search for princess stones with EGL certs so I can get the crown info.... I was surprised to find that there are quite a bit of stones out there with tables equal to or a little larger than depth that have crown heights above 10. I was quite surprised....!

They could also make for amazing sparklers!

 

[moremoremore]

here is an example - I would never think this stone would have a 12% crown! I've been finding stones with table less than depth but have 8%. Really odd. Chin up- finding a good princess is hard...but well worth it!

http://www.whiteflash.com/princess/Princess-cut-diamond-631467.htm#

 

[moremoremore]

I just don't understand!

.... I would think this one would be flat as a pancake!


http://www.whiteflash.com/princess/Princess-cut-diamond-648499.htm#

 

[Nicrez]

Crown hight and other measurements ARE absolutely important, and so that is definately going to be a factor. More is totally right, EGL has a lot more measurements than GIA...

But from what I noticed, these shallow pools of light are a result of a larger table and low crown, which usually accompany each other, but not always. That's why pavillion angles help.

Did you see the AGA Charts

A very helpful tool to see efficiency of cut, and sometimes it realy helps to weed out some uglies that the average lay person will not notice first hand. But ALWAYS see the stones, if you can!

Also, for kicks, you can get an Ideal-Scope on line, and go into that store and compare the stone's leakage in that "ring of death". try finding some AGA "well cut" stones, and see what they look like, or surf into GOG's sight to see some truly bright sparklers, and get a feel for how light is supposed to refract on a princess...

 

[taddles]

Thanks for the help on this. I've been debating whether to get an Idealscope or not, and may just purchase one for this reason. I have been looking at the AGA charts, but have had a hard time finding anything to look at in person that falls within the upper parameters.

These charts provide me something to look for, but beyond the Table and Depth %, I'm pretty much clueless. I previously wasn't paying much attention to Crown Height, but sounds like I should start looking at all three factors.

Thanks for the help

 

[moremoremore]

seriously, it's a gamble either way. Unless you're going with a jeweler who has lots of fancy schmancy analysis equipment, then I think buying an idealscope is a good idea. But I'm CONVINCED.... it's all about seeing the princess....don't eliminate a potential stone just b/c it's not a "1A" !!! What size, color are you thinking of getting?

 

[Nicrez]

Just remember that people make a living out of such studies, so you'll probably never be a pro, BUT understanding that a stone needs good complementary angles to the light entering to make it work it's best. Although the example is for a round, it's still and excellent want to see how depth and table determine optics on a stones Cut tutorial

Good luck and let us know how it goes!!!

 

[taddles]

I've been look in the 1.2-1.3 ct range, F-G color, VS2 clarity (give or take on this).

Does seem like it there's alot to learn and I'm just waiting for that one stone I view to "I'm the one".

 

[moremoremore]

I think they are a little odd at times, but they have some great stuff and policies.... Diamondbrokersooffl.com They carry the great quality stuff...they own it and can send you pictures, analysis, etc.... Here is one I saw 1.24 F Vs2 72.1, 71, Ex, Vg, $7050.

 

[valeria101]

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On 4/28/2004 3:24:40 PM moremoremore wrote:



I would never think this (72%depth,71%table) stone would have a 12% crown! I've been finding stones with table less than depth but have 8%. Really odd.

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Not toooo odd: large table and high crown just means a steeper pavilion... Thre are limits, sure that, and these numbers are averages of a much larger range than for rounds. This is why the AGA's are a blessing in disguise with lots and lots of info hidden in them

The EGL piece you pointed out gets the combination of depth (72%), table (71%) and crown height (12%) lined up for the 1B AGA type. For the same depth and table one would imagine 8% crown heigh is feasible, but with a different 'profile': the respective height would ask for a smaller table by AGA's wisedom (namely 59%-60%) and so on... The table below clearly takes into acount a tight range of crown angles (since table and crown height determined them with reasonable approximations for a near-square outline). The range of total depth for each category leaves pavilion angles to vary more but this for good measure: the cut of the pavilion could also vary quite a bit leaving the critique of this cut by numbers in the air (much more so than one can ask for in RBCs, HCA and all).

Does this make sense?

 

[taddles]

Wow, that's getting a little bit over my head, but if I'm understanding you correctly you are basically saying that I should look at the AGA chart as a set of numbers corresponding to each other. The tight range for each characteristic helps enable the quality of the cut. Thus, a stone with mixed characteristics from, say, 1B, 2A, and 2B probably wouldn't look as nice as something from that has all solid 2A or 1B measurements.

Either way, sounds like the chart may be a good tool to start and weed out stones, as has been said, but I ultimately have alot of stone-lookin' ahead of me.

 

[valeria101]

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On 4/30/2004 10:17:18 AM taddles wrote:



... if I'm understanding you correctly you are basically saying that I should look at the AGA chart as a set of numbers corresponding to each other. [...]

... but I ultimately have alot of stone-lookin' ahead of me.

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Yeah... this is it

It would make things easier to look for princess cuts with some test for optics in place (such as ready-made Ideal Scope pictures). GoodOldGold, Whiteflash (their "expert selection"), Niceice and some others go this route.

Also, some sellers make a more or less tight selection of stones by cut proportions (Dirtcheapdiamonds, Blue Nile...).

Obviously such selection is made for a premium, but you will find serious price variation among stones anyway and the price reference from a broader serch (including your locals and teh rest of the NET

) is always there