Polishing Girdle Effects

[DBM]

Hi. Can the experts tell me what the general concensus is of the effect of polishing the girdle on a diamond''s color is? I''ve been hearing arguments both ways.. thx

 

[JohnQuixote]

Date: 6/29/2007 12:12:21 PM
Author:DBM
Hi. Can the experts tell me what the general concensus is of the effect of polishing the girdle on a diamond's color is? I've been hearing arguments both ways.. thx

Some cutters believe polishing the girdle causes color to be reflected back inside, so unfaceted girdles are common in J or K color grades and down, and in small goods, .25 and lower. In near-colorless diamonds it's not the concern that it is with slightly colored and below. However, for those who make it common practice, the idea of leaving the girdle frosted (bruted) is with the intent of improving face-up color appearance.

As I recall, master stone sets must have unpolished girdles to get the thumbs-up from the major labs. I'm sure one of the appraisers here can comment on that.

For consumers who are interested, a polished girdle on a diamond is see-through or clear. A faceted girdle is one where the brillianteer polished facets into the diamond's girdle. An unfaceted, or bruted girdle is one where the diamond's girdle is unpolished and has a frosted appearance. Some newer girdling machines are putting what we call a "finely finished" girdle on some goods; more than bruted but less than polished.

 

[diagem]

No straight answer..., (in my opinion...)
There is the ''old saying'' that if you dont facet the girdle on a lower colored diamond it will add illusion of a whiter stone...

 

[DBM]

do you think leaving the girdle unpolished improves the actual face up color or just somehow frosts/obscures the diamond''s color look when turned over on a white color card.

 

[JohnQuixote]

Date: 6/29/2007 12:48:54 PM
Author: DBM
do you think leaving the girdle unpolished improves the actual face up color or just somehow frosts/obscures the diamond's color look when turned over on a white color card.

The notion is that light is reflected back inside by a polished girdle, exaggerating body color when present. This is debated, but it's interesting that the major labs will only endorse diamonds with unpolished girdles as master stones.

 

[diasurfer]

Is it possible to tell if a girdle is faceted or polished by looking at the certification? Does AGS Ideal polish imply that the girdle is polished?

 

[WorkingHardforSmallRewards]

Well, it says it is faceted if it is faceted and I am pretty sure that along the same lines if it doesn't say anything about the polish then that means it is polished. Otherwise it will note that it isn't polished but I have forgotten the terminology used as pretty much all modern girdle's in the common Ering color ranges at least are polished. I could be wrong I suppose, but that is what I recall learning.

Also, per Ideal requirements I don't think that the girdle being polished or faceted has any affect on the rating right?

 

[Lynn B]

My AGS-0 2.36 J RB has the kind of girdle that John discussed above. Not bruted, not polished/faceted... but some happy place in between.

Also, FWIW, when I had it appraised, the appraiser described it as "polished". All I know is that it's lovely and certainly doesn't take "anything away" from the beauty of the stone.

 

[surfgirl]

Can one of the experts speak about the effects, if any, of very/extremely thin girdles on color, etc.? I''m just curious since my I color transitional cut faces up very white in most lighting circumstances. Does a very thin girdle have an effect on that as well, or no?

 

[WorkingHardforSmallRewards]

Date: 6/29/2007 1:00:07 PM
Author: JohnQuixote

Date: 6/29/2007 12:48:54 PM

Author: DBM



The notion is that light is reflected back inside by a polished girdle, exaggerating body color when present. This is debated, but it''s interesting that the major labs will only endorse diamonds with unpolished girdles as master stones.

Don''t forget, this is debated

.

 

[JohnQuixote]

Date: 6/29/2007 8:03:25 PM
Author: WorkingHardforSmallRewards

Well, it says it is faceted if it is faceted and I am pretty sure that along the same lines if it doesn't say anything about the polish then that means it is polished. Otherwise it will note that it isn't polished but I have forgotten the terminology used as pretty much all modern girdle's in the common Ering color ranges at least are polished. I could be wrong I suppose, but that is what I recall learning.

It depends on who's reporting. Most reports say 'faceted' if it's faceted and 'polished' if it's polished - and sometimes finely finished - but we've seen reports where finely finished girdles had no comment.

Also, per Ideal requirements I don't think that the girdle being polished or faceted has any affect on the rating right?

Correct. A frosted/bruted girdle is not a detriment.

 

[JohnQuixote]

Date: 6/30/2007 12:52:36 AM
Author: surfgirl
Can one of the experts speak about the effects, if any, of very/extremely thin girdles on color, etc.? I'm just curious since my I color transitional cut faces up very white in most lighting circumstances. Does a very thin girdle have an effect on that as well, or no?

No effect on color, though too thin can be a durability consideration. An extremely thick girdle may impact light performance by adding darkness to the center of the stone, but that's dependent on specific shape/configuration - and such a stone would be penalized for weight ratio by responsible labs.

 

[diagem]

Date: 6/30/2007 12:58:43 PM
Author: JohnQuixote

Date: 6/30/2007 12:52:36 AM
Author: surfgirl
Can one of the experts speak about the effects, if any, of very/extremely thin girdles on color, etc.? I''m just curious since my I color transitional cut faces up very white in most lighting circumstances. Does a very thin girdle have an effect on that as well, or no?

No effect on color, though too thin can be a durability consideration. An extremely thick girdle may impact light performance by adding darkness to the center of the stone, but that''s dependent on specific shape/configuration - and such a stone would be penalized for weight ratio by responsible labs.

The thicker the girdle..., the more it becomes a concentration area for color...
It could change a graders opinion when grading the Diamond face down in a white color grading sheet.

Less a problem for Rounds..., but can be a serious problem for Fancy Shapes.

 

[JohnQuixote]

Date: 6/30/2007 1:13:07 PM
Author: DiaGem

Date: 6/30/2007 12:58:43 PM
Author: JohnQuixote

Date: 6/30/2007 12:52:36 AM
Author: surfgirl
Can one of the experts speak about the effects, if any, of very/extremely thin girdles on color, etc.? I''m just curious since my I color transitional cut faces up very white in most lighting circumstances. Does a very thin girdle have an effect on that as well, or no?

No effect on color, though too thin can be a durability consideration. An extremely thick girdle may impact light performance by adding darkness to the center of the stone, but that''s dependent on specific shape/configuration - and such a stone would be penalized for weight ratio by responsible labs.

The thicker the girdle..., the more it becomes a concentration area for color...
It could change a graders opinion when grading the Diamond face down in a white color grading sheet.

Less a problem for Rounds..., but can be a serious problem for Fancy Shapes.

We''re saying the same thing DG. I was the one who brought thick into it - for the reasons you state.

 

[diagem]

Date: 6/30/2007 1:17:05 PM
Author: JohnQuixote

Date: 6/30/2007 1:13:07 PM
Author: DiaGem

Date: 6/30/2007 12:58:43 PM
Author: JohnQuixote

Date: 6/30/2007 12:52:36 AM
Author: surfgirl
Can one of the experts speak about the effects, if any, of very/extremely thin girdles on color, etc.? I''m just curious since my I color transitional cut faces up very white in most lighting circumstances. Does a very thin girdle have an effect on that as well, or no?

No effect on color, though too thin can be a durability consideration. An extremely thick girdle may impact light performance by adding darkness to the center of the stone, but that''s dependent on specific shape/configuration - and such a stone would be penalized for weight ratio by responsible labs.

The thicker the girdle..., the more it becomes a concentration area for color...
It could change a graders opinion when grading the Diamond face down in a white color grading sheet.

Less a problem for Rounds..., but can be a serious problem for Fancy Shapes.

We''re saying the same thing DG. I was the one who brought thick into it - for the reasons you state.

Sorry..., I didnt read it that way..., I read the "no effect on color"...