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Understand OEC's; different cuts and light performances


Aug 28, 2016
If am a total newbie in the world of diamonds and OEC's (in which I am interested) and I would like to understand better the differences in the different cuts, and possibly how the cut affects their appearance.
My curiosity derives from the concrete case of my wife's rings and earrings;

First ring (The big):
Certified by a local unknown lab
Measurements mm: 15,93 - 16,00 x h 7,86
Weight: 12,54ct.
Clarity grade: SI 1
Color grade: L
UV fluorescence: Medium
Proportions: fair
Table: 49,4%
Crown height 13,2%
Pavilion depth: 35%
Total depth: 49,2%
Simmetry: Fair
Polish: fair

Second Ring (the beautiful)
Certified by a local unknown lab (not the same lab of the previous one)

Measurements mm: 10,32-10,51 x 6,73
Weight: 4,55ct.
Clarity grade: VS 2
Color grade: Q-R
UV fluorescence: Weak
Grille: bruted
Culet: Large
Simmetry: Good
Polish: fair

Proportions are not certified but total depth should be (according to measurements) around 64%

Earrings are not certified but the jeweller who made the setting for both rings told be the weight should be around 4,5ct and the color an R.

The 4,55ct ring seems to be, compared to the 12,55ct one, much more "alive" with more personality and a nicer light.
Is this due to the cut?
Moreover, in the "little" i can recognise a geometry (quite a floral pattern" while the big one seems to have just random facets and no recognisable pattern....
Am I looking at them in the wrong way? what should I look at?
Thanks a lot for your help!

Here some pictures (already posted in a previous thread I did open regarding the 12,55ct ring) and some new pictures I took with a macro lent (x10)










Jan 11, 2006
OECs were each individually cut and not to a strict formula like modern stones (such as hearts and arrows) may be cut. So each one is unique. Like any diamonds, some are more beautifully cut than others. Some have better facet patterns and light return. I think the 4.55 ct diamond has a beautiful facet pattern! The 12 ct diamond may not be as beautifully cut. Some people are purists and would never touch an antique stone, even if a mediocre to poor cut. Others would consider partial or full recutting to make the stone outstanding.

I can't tell how I feel about the 12 ct stone just from these pictures, but given that I can't imagine wearing a 12 ct diamond, I would personally consider the recut to make it a slightly smaller magnificent stone if the cut is not great. As I said in another post, an outstanding cutter of antique style stones is Yoram F., and you can contact Good Old Gold in NY if you are ever interested in exploring it.


Sep 11, 2012
You have summed it up quite nicely.
the 4.55 is quite a performer compared to the 12ct. That is purely based on the cut of the diamond. the better the cut, the more it reflects light. antique cut stones, also seem to pickup colour from it surroundings more than modern cuts, from what i can tell. i like the broader flashes of light that the antique cuts give off compared to a modern cut stone.
the 4.55 patterning is more distinct than the 12. The flowery pattern for me is what i see an OEC.

I do not mind if they are not perfectly flowery, but flowery none the less. in the 2 stones that you have, i much prefer the 4.55 patterning.

As DS pointed out, there are purists out there that would have the stone any which way it comes, as it is a marvel that they were cut in candle light many moons ago. And, to achieve what they have done in those conditions is truly remarkable.

For me: i would explore the option of having someone look at touching up the 12ct, to give the patterning more structure and with that more performance/ sparklier/ livelier.

Yoram/ GOG or Adam from old world diamonds will give you an idea of what to expect.. what loss of weight to expect and therefore resulting caratage of your stone. You will have to weigh up the options of the financial cost of doing this v the cost of the lost of weight v the overall increased performance of the diamond.


Aug 8, 2005
I agree. I would have the 12 carat's faceting optimized.


Aug 28, 2016
Thanks for all your answers, but I must admit I am a little bit confused now :confused:
In a previous thread where I was trying to understand the insurance value of the 12ct stone everybody suggested to not recut it, but now opinions seems to be different...

Could you maybe explain me what "facet optimisation" means? is it different than recut to get an MRB with decent proportions?
Just to understand, in case of "optimising" the facets how would GIA classify the stone? still as an OEC or as an MRB with a very poor cut?

I could not find any picture of OEC's >10ct do you have some to post here or links to share, so that I could understand how e "nice one" looks like?
Today I had some fun in trying to get the best out of both stones (I am still an amateur but, I hope, getting better), I hope these new pictures can help you in helping me :)








Sep 11, 2012
For me, I would not get this OEC recut to a MRB, as i am not a fan of MRB.

And, i am speculating that others on the other thread are suggesting the same.

As for facet optimisation, i would say that it would mean that the facets reflect in the best possible make that baby sparkle.. just like your 4.55. You have already made that assessment that you 4.55 is livelier than your 12. so, a recut in keeping with the current style, will give you a better performing stone. However, i WOULD not get it recut to a MRB.

When these facets reflect the light in the right way, what i have seen is that the patterning is very much like a flower pattern, like that of your 4.55ct

Also, newly cut stones that look like the old stones are AVR, a line that GOG carries.
here is an example of one; note the centre of the stone looks like a flower.
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