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How To Look At Diamonds For Brilliance


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Is there a limit to the amount of topics one can start? :rolleyes:


I'm looking at round brilliants w/ cut rated VG/EX by GIA. Similar colors, etc. Any tricks of the trade for how to actually tell which one is more briliant by looking at them w/ plain eyes? All I do is sort of let the eyes zone out and rotate the two diamonds in the light to see which one "sparkles" more. In flat light I honestly can't tell much of a difference between any. Any other suggestions?

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I could be cynical, and suggest that if the difference doesn't hit you in the eye then it's not money well spent...


To be honest, sometimes the differences are truly difficult to see, particularly if you can't do side-by-side comparisons. Like in any other area, there is a process of "getting your eye in" which takes time and many repeated observations for your eye/brain system to learn how to spot the clues.


To top it all off, cut standards particularly in RB have improved a lot, to the extent that if you look at GIA or AGS graded stones it's pretty difficult to see something in the bottom grades for cut. While a high cut grade is not per se a guarantee of excellent performance, it's not a bad place to start.


Bear in mind that you need to see diamonds under different types of light to evaluate different optical characteristics. For example flat (diffused) light is good for assessing brightness (i.e. the amount of total light the diamond reflects back); to evaluate scintillation (amount of spark-like white light) and fire (coloured sparkles) you need a more focused light source such as a spotlight.


The two articles here (http://www.gia.edu/research/156/gia_on_diamond_cut.cfm) may help with some pictures and much more detail.


Do ask the dealers to show you what they see and why they assess one particular stone as better than another. Keeping a skeptical frame of mind is a good thing, but you will need to trust someone with your hard earned cash at some point, and I find that hearing people talk about their goods in great detail is a pretty good test to figure out who really knows from who is simply peddling his wares, as long as you have some knowledge yourself, and you apply the Reagan logic of "trust but verify".

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Or if you can't see the diamond itself, we have two technologies that actually measure the diamond for brilliance ( white light) colored light and scintillation. One of our technologies even measures for optical symmetry.


We use these two technologies:




For instance, this stone which is a1.04 ct. VS1 G which is ideal cut and hearts and arrows.




1.04ct. VS1 G Live report

Edited by jan
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