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Which cut shines the brightest?

AV_

Ideal_Rock
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Aug 5, 2018
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3,363
The simple step cuts are the brightest - like mirror shards, very different animals than round brilliants; even small-ish stones act like little signalling devices as worn. At some size, I want a few more facets [too much to tell!], but not too many more www , www ... [ie. agreeing with @Garry H (Cut Nut) ]

Round brilliants at their best work as if the above-mentioned mirror surfaces were folded - brighteness does add up slice by slice, through movement, so no one can say the finest brilliants are obviously less bright, yet the brightest flash cannot happen.
 
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Texas Leaguer

Ideal_Rock
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I know Round cuts sparkle the brightest historically. Can someone tell me about Princess cuts & their fire??
Fire and brightness are actually two related but somewhat independent factors. Princess is a brilliant style cut capable of nice brightness and fire. But they have traditionally been cut with very flat tops for maximum carat weight yield which significantly reduces fire.

AGS Laboratories uses a sophisticated ray tracing technology to quantify brightness, leakage, contrast, and fire. If you stick with an AGS Ideal cut princess, you will have an optimal combination of brightness and fire.

Here's an article about fire that you may find helpful.
 

Karl_K

Ideal_Rock
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A princess cut in theory could be cut that is brighter than super ideal rounds by some measures but you will never see them on the market because the numbers are weird and the spread sucks.
Someone tried cutting some that were closer to that than the common princess cut and even the ags0 ones left on the market but gave up because the numbers were to weird for the market even though they had reasonable spread for a princess cut.
The other weird thing about the princess cut is that they could perform very well with no crown just a thick girdle.
 

Matthews1127

Ideal_Rock
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I agree with the above...all of the above.
Brilliant cuts sparkle, but step cuts throw fire like crazy.
If you want a fireball and you prefer the square shape of the Princess Cut, look at Asschers, Carre, Square EC’s, and Square Step Cut Diamonds.
 

Garry H (Cut Nut)

Super_Ideal_Rock
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I know Round cuts sparkle the brightest historically. Can someone tell me about Princess cuts & their fire??
Scintillation and binary rivalry though count more than you can imagine.

At any one time 20% or so of a round brilliant is dark to an observer at say 14 inches 35cm. The white stars in H&As or the black in Ideal-scope or the blue in ASET. but as you move the diamond or look with 2 eyes or both that stone is brighter than the carre that is like a boring mirror.
 

EAB

Rough_Rock
Joined
Feb 20, 2014
Messages
44
This is all so interesting as I’ve never thought about brightness and fire being two different things per se. I think I’m drawn more to the fire than the brightness. If looking online for a MRB with more fire is there a way to read the numbers that would steer you in the right direction? Or is this something you need to see in person?
 

Matthews1127

Ideal_Rock
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This is all so interesting as I’ve never thought about brightness and fire being two different things per se. I think I’m drawn more to the fire than the brightness. If looking online for a MRB with more fire is there a way to read the numbers that would steer you in the right direction? Or is this something you need to see in person?
If you want a fireball with both scintillation and fire, you should seek out WF, BGD, HPD, and any other vendor I’m neglecting to mention who carries and markets IDEAL CUT MRB’s.
Otherwise, you should consider experiencing an old cut round like the OEC’s and OMC’s. The broader the facet, the more flash/fire.
 

EAB

Rough_Rock
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Feb 20, 2014
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Thank you Matthews1127, I actually already spend an embarrassing amount of time on these sites, looking and learning. I guess I’m just wondering if there’s any clues in the numbers, angles etc that specifically read “fire” in the ideal cuts, or is it just something that is individual to a specific stone? Assuming one is looking at diamonds with comparable specifications in clarity, color?
 

Matthews1127

Ideal_Rock
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Thank you Matthews1127, I actually already spend an embarrassing amount of time on these sites, looking and learning. I guess I’m just wondering if there’s any clues in the numbers, angles etc that specifically read “fire” in the ideal cuts, or is it just something that is individual to a specific stone? Assuming one is looking at diamonds with comparable specifications in clarity, color?
There are ways of assessing fire.
There are angle and % combos that create fire.
Any GIA graded MRB stone’s specs can be calculated using the HCA tool.
AGS graded stones are graded using different standards than GIA, and don’t necessarily require HCA tool assessment to guarantee ideal proportions.
 

DevonRex

Rough_Rock
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Mar 15, 2020
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Like you EAB I too, have spent sooo many hours on research on this site deciding which diamond for my ring. LOL, but I do reearch any purchase to death which drives my family crazy !!
 

Paul-Antwerp

Ideal_Rock
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Princess fire is great in +5ct and crap below 2ct.
the brightest would be carre square or baguettes
As a general rule, always distrust a person throwing out a generalized blanket statement. Then again, my own reply here is also a generalized blanket statement, I now realize.

Live long,
 

Rockdiamond

Ideal_Rock
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Never, EVER, trust people who speak in absolutes.
Good point Paul!!
Lol
 

Karl_K

Ideal_Rock
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While a well cut mrb can have very nice fire in the right lighting if what your seeking is the most fire the most of the time you will not find it in a mrb or a princess cut.
They are both tuned for white light return by design.
 

Rockdiamond

Ideal_Rock
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To me, a discussion like this is why I’ve always felt that the science behind measuring light return/ LP, while providing valuable data, still misses a very crucial point. So much of which stone is “Brightest” has to do with personal preference.
 
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