modern cushion VS antique cushion

[valeria101]

speaking of your friend the OMC cutter... can we see any of his work ?

 

[Hest88]

Here''s my OMC. The lighting''s not great, but you can see the faceting. I loved playing with it when it was loose because because I could admire all the chunky facets.

 

[SJS1234]

Hest I LOVE your OMC!!! it is soooooo BEAUTIFUL!!!

 

[diagem]

ANA,

yes i can probably convince him to get me some pics of his OMC's, but you will need to teach me how to post them....

or you can contact my pvt.

 

[diagem]

ana,

or contact me privatly.

 

[diagem]

Ana,

Is there a chance that the OMC pics will be posted?? Is it working for you??

 

[valeria101]

Got one ! Here it is...

What are the stats of the marvel ?

 

[valeria101]

same, full scale... This stone seems to have one thousand facets !

 

[diagem]

2.03 cts.
7.00x7.09 mm.
78% total depht
52% table
Crown height 25%
Pavilion angle 46%
V. Thin Girdle
culet: Large
F- VS1

 

[diagem]

No not 1000, just 58 facets!!!

but applied the right way!!!

 

[Carolina Girl]

DiaGem, tell us if this stone is from the cutter you mentioned that is cutting in the old style, but with better proportions?

 

[diagem]

Technology today enables beter toolings than 100 plus years ago!!!
So basicaly you can cut a diamond today in any shape or angle you want, except for the original diamond plane

Symmetry, and polish is more accurate than before, allthough I came accross some GOLCONDA diamonds that were cut back then in a unbelievable fashion of perfectness, even for these days!!!

That means that 150 plus plus years ago, there were some (you could probably count them on one hand) amazing cutters cutting the important ROYAL diamonds...

 

[valeria101]

Date: 1/26/2005 6:57:46 AM
Author: DiaGem
No not 1000, just 58 facets!!! but applied the right way!!!

It seems that those virtual facets need both large and steep crown angles to form... if I am right to say that repeated internal reflection of the pavilion do the trick (the drawing below attempts to show what this guess-timate is all about - feel free to laugh !).

Sometimes it is said that the optimization of the ideal RBC cut shortens the path of light through the diamond. Is this (hall of mirrors effect - or multiple internal reflections) what gets lost ?

 

[diagem]

Close but no cigar yet, you can get the same efect on a diamond that has steep srown facets and a shalow pavilion. there are no strict rules.

But you are right about the difference of the regular rbc and the omc.
The shallow rbc doesnt have the same mirroring effects as the omc because of the difference in the size of the facetss. the omc facets are much larger and wider....

but you are on the right track...

 

[yanekie25]

Great topic. I am still wondering about my stone which is called an old mine brilliant. It does have chunky facets, which you can see very clearly. I think it may be a old mine cut rather than a modern brillant cushion.

 

[moremoremore]

What a cool looking close up! Such interesting facets!!!
Yanekie- Did you buy from Mark? Give him a buzz, I'm sure he'll help...And check out your cert...what does the plot look like. This is the "modern" as per DBOF...
What's the description- old mine or cushion? There are so many variables I think it makes my head spin

*edited- duh, it says old mine...


"Modern Brilliant Cushion" as I use the term and see the term used by GOG, DBOF, Niceice (e/t the term doesn't really seem to exist LOL)

 

[moremoremore]

Here is the old mine...but then I bet yours is different b/c it says old mine brilliant. That sounds very unique!

 

[moremoremore]

Bingo- Old Mine Brilliant

We should start a thread with the different cushion plots. That would be very cool. I''ve seen nothing like that out there all in one place!

 

[moremoremore]

Another cushion from GOG. They post three plots for the traditional cushion...one is above (the old mine brilliant), and the third is below! THis is fun! I've seen others out there too!

 

[moremoremore]

!

 

[diagem]

One of the sketches that were posted (THE SECOND ONE ABOVE THIS POST) are used for fancy color cushion diamonds!!!!

But keep them coming, very interesting!!!!

 

[valeria101]

 

[valeria101]

This is one famous old mine version - the Regent (Hing''s Gem Cad version):

 

[valeria101]

One of the above comes with a radiant-style (or barion) pavilion, here''s one princess-look alike:

 

[valeria101]

What should I call this one ?

 

[diagem]

tHE REGENT DIAMOND WHICH WAS CUT IN 1700 IS CONSIDERED TO BE ONE OF THE FINEST SPECIMENTS.

ITS LOCATED AT THE LOUVRE IN PARIS, AND IS AMAZINGLY BEAUTIFULL AND PRECISE FOR A DIAMOND CUT 300 YEARS AGO.

IF ITS LOCATED IN THE LOUVRE MUSEUM, I GUESS IT HAS ENOUGH CREDIT TO BE CONSIDERED ON OF THE MOST BEAUTIFULL DIAMONDS IN THE WORLD TODAY.

 

[valeria101]

Another fancy color prone, steep upper girdle-d version ...

 

[valeria101]

Date: 1/27/2005 3:49:49 AM
Author: DiaGem

IF ITS LOCATED IN THE LOUVRE MUSEUM, I GUESS IT HAS ENOUGH CREDIT TO BE CONSIDERED ON OF THE MOST BEAUTIFULL DIAMONDS IN THE WORLD TODAY.

The Louvre collection has been actively seeking famous jewelry on the international market for decades... and much ends up in the basement ! Not sure they select loose diamonds for cut... as much as for weight though

Seriously... this is one famous example of thin pavilion facets added to improve brilliance. At least one other historic diamond has them, and so do a couple of modern cut brands. I could not believe they never mentioned such predecessorrs in the respective advertising campaigns

On the side... about the "cigar" mentioned yesterday. I could not find a simple rule of thumb for the virtual facets without taking the deep breath required for a proper demonstration. It seems that both the size of the crown facets and the angle between crown and pavilion mains needs to fall within given limits without a strict relationship between the two. Is there a way to pin down the look by numbers ?

 

[diagem]

Yes you are right, but the pavilion facets that are intersecting with the culet are polished at a shallow degrees, about 36 degrees. thats to make sure the color doesnt leak out...

The brillianteering of the pavilion have a major role in keeping the fancy color of the diamond even, when looking face up...

 

[diagem]

The regent diamond is considered by historians to be one of the most beautifull GEM STONES (not only diamonds) in the world today...

You have quite a few diamonds in the range of the regent weight ( 150 carats appr.) that the Louvre wouldnt dear display them.

GIA graded the REGENT''s symmetry and polish as very good to excelent, a rare grade for a diamond cut in 1704. Dont you agree?