Do RB''''s or OEC''''s face up larger in same carat size?

[skphotoimages]

I keep seeing pictures of OEC''s and am suprised when I see the ct size. They seem so much larger, which lead me to ask my question...Do RB''s or OEC''s face up larger in same carat size?

 

[Lorelei]

You would need to compare physical diameters.

 

[stone-cold11]

If cut ideally OEC should be smaller than a modern RB as it usually have a much higher crown thus more weight is hidden. But antique OEC might not be cut ideally which is maybe why you see the larger spread?

Karl did some schematics in this thread on OEC, transitional and modern RB.

 

[diagem]

Date: 1/28/2009 6:27:15 AM
Author: Stone-cold11
If cut ideally OEC should be smaller than a modern RB as it usually have a much higher crown thus more weight is hidden. But antique OEC might not be cut ideally which is maybe why you see the larger spread?

Karl did some schematics in this thread on OEC, transitional and modern RB.

Firstly..., no such creature as an "ideally cut OEC"...

Secondly..., why would you state a higher crown as "hidden weight"? Hidden where exactly?

 

[stone-cold11]

ok, not hidden, but in the crown and not in the spread.

And that is modern cut OEC. As you said, not such thing as ideally cut OEC and I also said that real OEC are not cut ideally.

 

[Lorelei]

Date: 1/28/2009 6:27:15 AM
Author: Stone-cold11
If cut ideally OEC should be smaller than a modern RB as it usually have a much higher crown thus more weight is hidden. But antique OEC might not be cut ideally which is maybe why you see the larger spread?

Karl did some schematics in this thread on OEC, transitional and modern RB.

SC, for your information, above implies that there is such a thing as an ideally cut OEC, just so you understand how others can interpret your advice in this post.

May I explain? " If cut ideally OEC should be smaller than a modern RB"...( this to me reads that you mean we are discussing an ideally cut OEC and therefore this cut standard in this type of diamond exists, also your statement that " antique OEC might not be cut ideally " also implies that an Ideal Cut OEC is available).

 

[diagem]

Date: 1/28/2009 7:04:08 AM
Author: Stone-cold11
ok, not hidden, but in the crown and not in the spread.

And that is modern cut OEC. As you said, not such thing as ideally cut OEC and I also said that real OEC are not cut ideally.

Ok..., I believe once the weight is not hidden..., then it becomes a factor of personal preference in conjunction with correctly cut proportions...

Some people prefer spread and some prefer a sculpture effect.

 

[Allison D.]

Date: 1/28/2009 1:31:37 AM
Author:skphotoimages
I keep seeing pictures of OEC''s and am suprised when I see the ct size. They seem so much larger, which lead me to ask my question...Do RB''s or OEC''s face up larger in same carat size?

In most instances, the OEC will face up smaller than a RB; the added crown weight comes at the expense of diameter.

A friend and I recently bought OECs; one is .84 (measuring 5.75mm) and the other is .86 (measuring 5.9mm). By comparison, a top-make RB stone of the same weight will display a diameter in the neighborhood of 6.10-ish mm.

 

[mrssalvo]

my formerly owned OEC was 1.2 carats and had a diameter of 6.5 making it similar in size to an ideal cut modern round.

 

[strmrdr]

generally slightly smaller.
A transition cut can be close to the same spread or even larger than some as angles and table sizes are similar.
A lot of transition cuts are close to 60/60s with slightly higher spread than the newer ideal cut standard.
The problem is there is a huge variety and finding an average for either oec/transitional is impossible.


That said there is a factor I call Z axis contrast which says that high crown diamonds look larger than the proportions indicate when well cut particularly when tilted.
So a high crown oec with light return out close to the edges may appear bigger than a modern RB in some cases.
That is just my feelings and what I see but some experts do agree it exists.

As far as I know the only idealish standard for oec/transitional performance is one I am working on in case I ever get a chance to have repro's cut.

 

[strmrdr]

link to a discussion on z-axis contrast:
https://www.pricescope.com/community/threads/z-axis-contrast-3d-the-forgotten-aspect-of-diamond-performance.80889/

 

[mrssalvo]

Date: 1/28/2009 11:52:47 AM
Author: mrssalvo
my formerly owned OEC was 1.2 carats and had a diameter of 6.5 making it similar in size to an ideal cut modern round.

too late to edit: I meant to say my 1.2 was similar in size to an ideal 1 carat round.

 

[beaujolais]

Karl,

In other words are you saying that the 3D effect in old high crown diamonds can make them appear larger? O.K., I could see that.

Say, I think you''d be just the person who should team up with a cutter and produce a line of repro antique cuts. As Storm Designs, we know they would be off-the-charts awesome, a good amount of people want these and it is a niche that needs to be filled.

 

[skphotoimages]

Thanks everyone!

 

[strmrdr]

Date: 1/28/2009 1:10:11 PM
Author: sonomacounty
Karl,


In other words are you saying that the 3D effect in old high crown diamonds can make them appear larger? O.K., I could see that. Yes


Say, I think you''d be just the person who should team up with a cutter and produce a line of repro antique cuts. As Storm Designs, we know they would be off-the-charts awesome, a good amount of people want these and it is a niche that needs to be filled. maybe once the economy picks up someone will bite and they will be produced

 

[oldminer]

The notion that there never was a time when the best example of an old European cut was not "ideal" in its own period is bogus. The Ideal diamonds we deal with today were not the best cut diamonds of 30 years ago. Time and fashion change and the word "Ideal" has no particular inherent meaning. It is a word which defines "todays' best examples" and is not some fixed target or goal that we have now achieved and forever will hold fixed.

I know we tend to think that what we have today is really something special and that we have "arrived". This isn't exactly true although we know far more about how to get beautiful diamonds today than was known decades ago. What we have achieved is communicating this knowledge to enough retailers and consumers that better diamond cutting is being demanded and widely accepted. Even chain retailers who generally sell secondary or worse cut diamonds now have made room for limited numbers of finer cuts although the mass market for them does not yet exist.

Every once in a while I used to come across an OEC diamond that was the perfect Tolkowsky make but with the pavilion faceting done in the old, shorter, style. These were highly attractive and could be said to be someone's idea of "ideal" although no one ever made that claim. They were pretty enough to sell without naming them.

An ideal diamond is a highly intelligent compromise between beauty and retained weight. The smallest details will make a huge difference in who may show interest in the stone and what it must sell for. I promise you that change is a certainty in what is considered to be "ideal" today in coming years or decades. What you can't take away is beauty and that is a personal preference not subject to fashion or economics.

Many OEC diamonds were spready and quite large for their weight, but lacked brilliancy due to thin total depth. Others were quite deep and looked very good in some lighting conditions, but not in others. Only a few were cut within the norms of acceptable modern cut depth. There are many good reasons why this all happened. You can expect to photos of the spready stones since they are photogenic. The deep ones just look smaller, so why show the image when you can talk about how nice they are instead? Everyone has to sell the benefits, not the detriments.