Question About GIA Certs for old stones (OEC, etc.)

[stevied]

So I''m looking at what an antique dealer called an Old Mine Cut (2.04 HSI1,8.14-8.28 X 4.95mm), and he pulls out the GIA Cert and it says Round Brilliant. I could''ve sworn I''ve seen GIA Certs with "OEC" and "Transitional Round Brilliant." Would the GIA say "OMC" if it was the case?

I fully understand that the distinctions among OECs, OMCs TRB''s and "modern" round brilliants are somewhat subtle, but I thought the GIA still reflected the fact that it is an old cut?

This particular diamond had a 59% table, 60% depth, 36 degree crown angle, 41 degree pavillion, extremely thin girdle and medium culet. Good P & S.

Thoughts?

 

[chrono]

It seems like this stone doesn't have the usual specs of an old stone. All the specs, including the angles sound like a modern 60/60 cut stone, hence perhaps that's why GIA calls it a RB? I mean, most tables of old cut stones run in the low 50s. Sometimes, in the high 40s. Depths are usually in the high 60s up to 80s.

 

[surfgirl]

Can you post a photo here? It would be easier to comment if we could see the stone you''re referencing.

 

[stevied]

Unfortunately, I don't have a picture. Here's a pdf of the Cert. I could only copy its bottom half to keep it under the 100kb limit.

 

[diagem]

Date: 7/16/2007 3:16:21 PM
Author: Chrono
It seems like this stone doesn''t have the usual specs of an old stone. All the specs, including the angles sound like a modern 60/60 cut stone, hence perhaps that''s why GIA calls it a RB? I mean, most tables of old cut stones run in the low 50s. Sometimes, in the high 40s. Depths are usually in the high 60s up to 80s.

When it comes to old-cuts..., there are no usual specs.
They come in all shapes and sizes etc..., etc...

 

[chrono]

Date: 7/16/2007 4:29:44 PM
Author: DiaGem

Date: 7/16/2007 3:16:21 PM
Author: Chrono
It seems like this stone doesn''t have the usual specs of an old stone. All the specs, including the angles sound like a modern 60/60 cut stone, hence perhaps that''s why GIA calls it a RB? I mean, most tables of old cut stones run in the low 50s. Sometimes, in the high 40s. Depths are usually in the high 60s up to 80s.

When it comes to old-cuts..., there are no usual specs.
They come in all shapes and sizes etc..., etc...

With specs like this, wouldn''t you say that one would NOT expect to see a pillowed top old cut stone? With such a (relatively) shallow stone and (relatively) large table, wouldn''t it look quite different?

 

[stevied]

I guess my bottom line question is -- putting aside this particular stone -- does the Shape and Cutting Style portion of the GIA certificates indicate "Old European Cut"; "Old Mine Cut" etc., or will it invariably say "round brilliant"?

 

[chrono]

Back to the topic at hand:
I have read on PS just last week that GIA will cert old cut stones as Old European and Old Mine Brilliant, not RB.

 

[pyramid]

A chart someone posted on the forum some time ago. Maybe the original poster knows this but notice the outline of an Old Mine Cut is squarish with rounded corners.

 

[stevied]

Date: 7/16/2007 4:43:41 PM
Author: Chrono
Back to the topic at hand:
I have read on PS just last week that GIA will cert old cut stones as Old European and Old Mine Brilliant, not RB.

Thanks, Chrono. That''s what I thought. This guy was supposedly a "reputable" estate diamonds dealer. Either he lied, or he simply does not know that a "Round Brilliant" should not be called an "OMC" if it''s no listed on the cert as such.

 

[diagem]

Date: 7/16/2007 4:39:49 PM
Author: Chrono

Date: 7/16/2007 4:29:44 PM
Author: DiaGem

Date: 7/16/2007 3:16:21 PM
Author: Chrono
It seems like this stone doesn''t have the usual specs of an old stone. All the specs, including the angles sound like a modern 60/60 cut stone, hence perhaps that''s why GIA calls it a RB? I mean, most tables of old cut stones run in the low 50s. Sometimes, in the high 40s. Depths are usually in the high 60s up to 80s.

When it comes to old-cuts..., there are no usual specs.
They come in all shapes and sizes etc..., etc...

With specs like this, wouldn''t you say that one would NOT expect to see a pillowed top old cut stone? With such a (relatively) shallow stone and (relatively) large table, wouldn''t it look quite different?

Chrono..., there is a difference of what people are used or educated in regards to identifying old-cuts...
But I am sorry, there are no rules when it comes to old-Antique cuts!

I have seen some drop-dead gorgeous flat (crown and pavilion) old cuts.

 

[diagem]

Date: 7/16/2007 4:43:41 PM
Author: Chrono
Back to the topic at hand:
I have read on PS just last week that GIA will cert old cut stones as Old European and Old Mine Brilliant, not RB.

As far as I know..., the GIA will identify OMB''s based on specific requirements...
I have never seen a OEC identified GIA report yet!!!

I strongly believe they should, but I have not seen one yet.

 

[Modified Brilliant]

Date: 7/16/2007 5:57:02 PM
Author: DiaGem

Date: 7/16/2007 4:39:49 PM
Author: Chrono


With specs like th

Date: 7/16/2007 4:29:44 PM
Author: DiaGem

Date: 7/16/2007 3:16:21 PM
Author: Chrono
It seems like this stone doesn''t have the usual specs of an old stone. All the specs, including the angles sound like a modern 60/60 cut stone, hence perhaps that''s why GIA calls it a RB? I mean, most tables of old cut stones run in the low 50s. Sometimes, in the high 40s. Depths are usually in the high 60s up to 80s.

When it comes to old-cuts..., there are no usual specs.
They come in all shapes and sizes etc..., etc...

is, wouldn''t you say that one would NOT expect to see a pillowed top old cut stone? With such a (relatively) shallow stone and (relatively) large table, wouldn''t it look quite different?

Chrono..., there is a difference of what people are used or educated in regards to identifying old-cuts...
But I am sorry, there are no rules when it comes to old-Antique cuts!

I have seen some drop-dead gorgeous flat (crown and pavilion) old cuts.

This is very true, DiaGem.
Many dealers and retailers use the term "Old Mine Cut" when in reality, it could be an "Old European Cut."
Some really don''t know the difference or the difference is not obvious to them.
Others use the term "transitional cut" if they''re not sure....covers just about anything old that might have some modern characteristics.

www.metrojewelryappraisers.com