Need help evaluating oval diamonds

[Serg]

David,

Seems you missed my main statement about color in ovals.

"Softer white"=yellowish would be fine if color has uniform distribution in diamond crown pattern. Uniform "Softer white" color can be even invisible , specially in yellow gold settings .
The problem is the unevenness in color pattern due different length path's for different cut parts. Oval cuts usually have such unevenness in color pattern. it become easy visible for I colors and it does not looks nice.
also it does some oval parts more dark, less brilliant. You would easy see it in comparison with better colors.

HI Serg,
I think we probably agree than many- or even most ovals are not very well cut. The reason I feel our locations may impact the type of advice we'd give is that we may see very different types of oval diamonds on a daily basis. IMO "usually" does not matter to any single specific diamond.
I have found some lovely OMB's in I-K colors- the nicest ones do not show an uneven color.

Based on the the shape of an oval, when you superimpose the Brilliant Pavilion design from a round ( OB), you're going to have main facets on the pavilion that vary widely in terms of shape and size. The different sized pavilion mains may also cause unevenness in color. Because of this aspect, sometimes the OMB design can produce a more even result.



Another aspect of this discussion that I find to be very important is that if we accept the fact that any oval diamond of I-J color is not worth considering ( which I do not), we're eliminating some viable candidates.
Same thing with ASET and the limitation of it.
If ASET imagery causes viable candidates to be eliminated, then consumers are pushed into higher colors, or smaller stones for their budget.
I-J color is not for everyone, but some people prefer it to a D

Hi David,

Technically there are not any problem to receive OMB with uniform color. There are many oval designs for fancy color diamonds that produce nicely uniform color .
but if cutter use such design for "I" color oval ,he usually can not receive any profit.
1) OMB Lab grade from Pavilion is typically worse than for OB( from same rough). for example "K" color instead "I" color
2) From crown the diamond looks as L-P color
3) VF's are small ( too small for "colorless" diamonds)
4) for some types of spectrum the crown color would be too dark. Yes there are rough with good spectrum that creates opportunity for bright oval with inform "warm color" if a cutter use good fancy color cut design. But to often a cutter will receive "dark brownish color" instead "warm white". Most cutters have not technology to select cut depends from rough color spectrum . without special technology the risk is to high, profit is to small and very rare. if he use such technology then expenses to high in compare with Oval "K" color price per carat .

I prefer " K" color oval with uniform color instead "I" color oval with uneven color, "white bowtie", ..
but such choice is not profitable for cutters.
sometimes you would see nicely cut P-T Ovals with uniform color due cutter mistake! a cutter selected fancy color oval design, because he expected to receive Fancy light color. He lost money, you received nice oval with uniform "white warm" color. wrong market, weak color grading system.

 

[Serg]

Brilliant pattern is fine only for round girdle shape. Some OMB is much worse than OB but some OWB is better than best OB. Good colorless OWB is very rare and it is not easy to find. You selected very interesting sample but "I" color is bad choice for such cuts.

First of all, a huge thanks to Gypsy in answering my question in such details with examples. It will take me some time to look over your posts in detail. I am sure that I will have some more questions in a few days.

Just for some clarification: Serg -do mean OMB when you typed 'OWB' in your previous post? You mentioned that a good colorless 'OWB' is very rare. Is it because it is a difficult cut such that cutters are no longer trying to cut this shape or there is just no demand for it?

Also, yennyfire, your avatar ring is beautiful! Is antique oval equivalent to a OMB cut or not necessarily? Where can you find antique oval cuts in general?

Thank you, PS community!

Hi lb0424,

Yes, it has to be OMB, sorry for strange misprint.

there are many reason why good OMB are rare:
1) technologies to cut standard OB is a little bit more simple than to cut OB.
2) market less respect any "Modified " cut. some consumers and "experts" consider modification as cheating from cutters with goal to receive better yield .
3) there are not technology to select good fancy cuts. Cutters would receive some premium for symmetry, for good ASET image , but usually they can not receive premium for optical performance .
4) It is very difficult to develop and produce Oval design with uniform VF pattern.

I forgot most important the reason
0) * OMB color Lab grade from Pavilion is typically worse than for OB( from same rough)* for example "K" color instead "I" color

 

[Serg]

Brilliant pattern is fine only for round girdle shape. Some OMB is much worse than OB but some OWB is better than best OB. Good colorless OWB is very rare and it is not easy to find. You selected very interesting sample but "I" color is bad choice for such cuts.

First of all, a huge thanks to Gypsy in answering my question in such details with examples. It will take me some time to look over your posts in detail. I am sure that I will have some more questions in a few days.

Just for some clarification: Serg -do mean OMB when you typed 'OWB' in your previous post? You mentioned that a good colorless 'OWB' is very rare. Is it because it is a difficult cut such that cutters are no longer trying to cut this shape or there is just no demand for it?

Also, yennyfire, your avatar ring is beautiful! Is antique oval equivalent to a OMB cut or not necessarily? Where can you find antique oval cuts in general?

Thank you, PS community!

Hi lb0424,

Yes, it has to be OMB, sorry for strange misprint.

there are many reason why good OMB are rare:
1) technologies to cut standard OB is a little bit more simple than to cut OB.
2) market less respect any "Modified " cut. some consumers and "experts" consider modification as cheating from cutters with goal to receive better yield .
3) there are not technology to select good fancy cuts. Cutters would receive some premium for symmetry, for good ASET image , but usually they can not receive premium for optical performance .
4) It is very difficult to develop and produce Oval design with uniform VF pattern.

I forgot most important the reason
0) * OMB color Lab grade from Pavilion is typically worse than for OB( from same rough)* for example "K" color instead "I" color

I have just checked data. Sometimes OMB has worse Pavilion color than OB, sometimes vice-versa. It depends from cut pattern, girdle ratio, other proportions.

So my statement "OMB color Lab grade from Pavilion is typically worse than for OB" may be is not correct.

 

[Rockdiamond]

lb0424- again, please don't let this technical discussion interfere with your search- some of what we're discussing is way more detailed that a person shopping for a diamond needs to get involved with.
BUT- you did inadvertently start a very interesting esoteric discussion about oval diamonds.

Part of why I have always been against too much technical discussion about these details is that it can needlessly slant a consumer's outlook.
As an example- if someone asks about "light performance" when they call, I know for sure they have read this forum.
Thankfully we speak with hundreds of consumers in a given month, which gives me perspective.
The percentage of people aware of the term light performance is small.
When we speak of Oval Brilliant versus Oval Modified Brilliant the percentage of shoppers who are even aware of the distinction is tiny.
So, the "average' oval diamond shopper not only won't pay more for an OB ( for that reason alone), they won't even know to ask.

My perspective, and this has created some conflict here- is that unless someone really wants to learn this stuff, it's simply not necessary to learn the minutia to buy well.
IN fact, to much technical gobbledygook can even hinder a shopper.
Again, just looking at this discussion- my opinion is that lb0424 should use her ( or his) own eyes to determine what he ( or she) loves.
If someone who hasn't really seen a lot of diamonds is led to believe OB is "better than" OMB, that would affect what stones the shopper will want to see- and even how they see them.

Serg's perspective is as a scientist- the guy is brilliant. He is working on ways of improving diamond cutting and representation using scientific methods
Gypsy is one of the most helpful, and experienced people posting as a "prosumer". She's spent thousands of hours learning the technicalities as they are discussed here.
I'm a person who was raised in the diamond business as a trader. I only buy diamonds hands on.
So we each look at diamonds in a different way.

 

[BeekeeperBetty]

I've enjoyed the discussion. I posted a little bit back about the types of ovals and the history of the cut because I wanted to learn about mine, but I didn't get much response. I'm still trying to ferret through the facet patterns to see which one I have, but with the open culet it doesn't seem to fall in to any of them. I probably just don't know what I'm looking for.

Even though a good oval can be challenging to find, apparently (I bought the only one I've ever seen - never saw one before or since in real life), they are a gorgeous cut, and I adore mine. They are so flattering to wear and look wonderful with a number of different settings.

 

[Rockdiamond]

Here's a few reasons where my perspective differs from some of what Serg wrote- although he has retracted parts...
The modified pavilion design ( OMB) allows the cutter far more freedom to put facets where they want. This can help in yield, allowing them to cut a larger stone from the same rough if they cut to an OB)
But the OMB design also allows for tailoring the look specifically to the particulars of the stone. That can be color distribution, or light performance. They can place facets where they perform a specific job. OB handcuffs the cutter.
Is this "cheating"?
Well, the first time I heard anyone refer to it that way was Yoram. So maybe for the best cutters, that's how they see it.
My perspective is as a buyer.
Did the cutter loose money on this stone- or did he make a killing?
That does not matter to me at all.
Is the stone priced where it should be based on the market?
Now, that matters.
If the cutter made a mistake, that's their problem.

Same for comparing OMB versus OB.
Cutting an OMB is not cheating- it's a manner of cutting. If an OMB looks great, it's worth far more than a OB with a honker static bow tie.
I am lucky in that I have worked with many cutters who've really spent a lot of time developing ways of utilizing the positive aspects of the Modified Brilliant design. Although Serg and I still agree that most stones on the market are not the top performers, my experience is that there are indeed examples of both OMB, and OB ovals that are amazing- even in J-K color

 

[lb0424]

Serg's perspective is as a scientist- the guy is brilliant. He is working on ways of improving diamond cutting and representation using scientific methods
Gypsy is one of the most helpful, and experienced people posting as a "prosumer". She's spent thousands of hours learning the technicalities as they are discussed here.
I'm a person who was raised in the diamond business as a trader. I only buy diamonds hands on.
So we each look at diamonds in a different way.

Thank you so much for everyone's effort in contributing to this thread. I am actually so grateful that as a consumer, I am able to interact with Serg (or cutters in general) to discuss about diamond. I am also thankful for Gypsy for showing me the ropes to become a 'prosumer' one day. I did some research on MRB and learned a lot about the light performance and 'ideal' angles. I found the science behind diamond cutting interesting and fun! But as Rockdiamond pointed out, it may not be necessary for all consumers.

I learned early on that it is more difficult to assess fancy shapes just by numbers so therefore I reached out to PS community for more information and now I got homework to do before I got more questions!