Brilliance from fancy shapes

[diamondlil]

I just saw a friend''s new 2 ct AGS000. It absolutely knocked me over!

Although it is a G color, it was whiter and certainly more brilliant than my E color pear (cut class 2B). My question is about the amount of brilliance lost in the cutting of fancy shapes. If all specifications fall within the AGA cut class 1A, how much less brilliant would a fancy-shaped diamond be as compared to a round brilliant?

I''m not a fan of how a round stone looks on my long fingers so I can''t see myself changing to a RB, but I can''t get out of my mind''s eye how georgeous this ideal stone looked! If I were to find another pear with all specs in the 1A category, would it be significantly more brilliant than my 2B?

Diamondlil

 

[Michael_E]

diamondlil,
Sorry, by their nature fancy shapes, pears and marquises in particular, will never have the brilliance of a round cut stone. If you look at how light bounces around inside a gemstone, those long thin ends always shoot light off in the wrong directions. Here's a screen capture of a light ray entering the table of a pear shape. See how it's shooting out of a crown facet at a low angle. That's just the way fancy shapes are.

 

[Michael_E]

OOPS! Sorry about the big pic.

 

[diamondlil]

Is this to say that pear and marquise cuts are the worst with regard to light return? Would an oval or radiant be any better? If it were stated this in terms of percentages, would you say that a fancy shape is something like 50% less brilliant than a RB, or 30%, or what?

I'm trying to keep this in perspective from my pocket book's point of view: Fancies are less expensive per ct than RB (well cut of course), and I want to know the tradeoff (i.e. if a RB is twice the cost of a well-cut fancy, is it twice as brilliant?).




I would consider trading up to a better cut pear (AGA cut class 1A vs. 2B), and I'm wondering if I would get significantly more light return for my $$ by doing so. Or is changing to a RB the only way to get that *bling*? For starters, I'll never hold my ring up against my friend's AGS000 again -- heehee

.




Diamondlil

 

[valeria101]

Ovals are probably getting the closest to a RB's brilliance (one half at atime, literally, excepting that bow-tie zone). I have never seen that kind of % estimation for fancy shapes (similar 'estimation' is used for colored stones though, well not compared to RBC dimaond, but the concept is used). I would probably venture to say that a fancy would aspire to at least 80% of RBC's light return (best cut against best cut). I guess pears and marquises would be the lest likely to be found in cuts meant for light return. However, looking at GOG's stats for light return, there are enough fancies out there to match RBC sparkle! However, there will always be zones of inequal brilliance in fancy cuts... this is their way to be nice, I guess. However, there is no reason for a pear to blatantly lack sparkle. as you describe, or to make an E color look yellow

And no, diamonds are not yet priced according to their relative light return, there are other considerations for fancy cuts to be cheaper. I guess one reason is the more 'liberal' cutting parameters of the fancies which allow better use of more varied types of rough, and, more importantly, the (much) lesser demand for them compared to the RBC.

 

[diamondlil]

Thanks AnA. I would not say that my pear lacks sparkle or in any way looks yellow. When I purchased it, comparing it with my old stone, it was a huge jump in the right direction -- much whiter and much more sparkle. Of course in comparison to 99% of the stones I've seen on hands, I'd rank my pear near the top. I suppose that is because the "average consumer" knows even less than I do about diamonds -- which is not a whole lot, but I'm learning.




I had never seen a ideal cut RB AGS000 in person before, and I had no idea a diamond could be that spectacular. I would say I have looked at a lot of diamonds, but not of that cut quality. Maybe I will be rethinking the fancy shape decision and consider a RB more seriously.




Okay, I have definitely caught the "diamond disease." Once again, my husband is rolling his eyes at me when I try to talk to him about this -- heehee.

Diamondlil

 

[valeria101]

18:32 AM diamondlil wrote:
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I had never seen a ideal cut RB AGS000 in person before; maybe I will be rethinking the fancy shape decision and consider a RB more seriously.
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Diamond desease: you have no idea how bad is the colored gem syndrome, especially with crystalography complications! However, the diamond people seem to be quite imune to it...

Well, I am an undeterred fancy shape admirer, and I do believe that all shapes have excellent potential to allow for the very best light return parameters. However, until now there has been much less effort spent to maximize light return in fancy shapes... true enough, their geometry does limit the consistency of light return (meaning the tip of a pear will not be as brilliant as the body, or such) but they should fall darn close to the round. Since I do not make a living out of selling diamonds, I cannot really show you what I mean, but there are two examples at hand to demonstrate just how much room for (light return) imprevement there is left in fancies. All right, the FIRST pear would put a few rounds to shame, and is at quite a difference from the SECOND
However, neither has been cut with light return in mind. Immagine what potential this shape could have if someone actually would... Why sacrifice shape for brilliance? I would rather not confuse a jewelry store with an industrial optics lab, and the tradeoff does not have to be all that great. Do you know the light return specs of your pear?