How to tell if your diamond is severely DUG OUT?

[gladstone]

I am shy to tell people that the stone is AGS ideal knowing that the cutter took advantage of the manner by which the lab measure the gridle thickness. I believe one of our stone is severely dug out by a cutter to [hide] weight. The upper girdle facets appear dark in most lighting conditions.

I have a sarin of the stone. The girdle map look like a big fat belly at bezel & main junction. I do not have access to a scanner today. Is there some number on this sarin report that I can post in order for you to confirm that the stone is severely dug out?

Thank you in advance for you help...

Edited:

Here is the Sarin numbers:

Weight: 1.250
Diameter: 6.89 (6.87-6.92) [0.7%]
Total Depth: 62% 4.27mm
Crown Angle: 34.1
Crown Height: 14.4
Pavil Angle: 41.0
Pavil Depth: 43.4
Culet: 0.2 None
Table Size: 57
Girdle: 1.8% (1.4-2.2) Slight Thick

 

[whatmeworry]

gladstone, can you post your sarin? Or take snapshots of the sarin and post those?

 

[gladstone]

I have edited my original thread with the Sarin numbers. The carat weight is exactly 1.25. This is often a reason for cutters to dig and retain weight right?

 

[whatmeworry]

Gladstone,
Those girdle data numbers you posted are not the actual girdle measurements of your diamond. They are a guide for the old AGS system. AGS0 would have a girdle between 0.5 and 3.0, AGS1 would have have a gridle between 0.1 and 3.0, etc. For example, you girdle is 1.8 so it gets a 0 grade. Can you post the girdle map with the fat belly?

 

[gladstone]

I draw this with Paint. This is what it look like. I will scan the girdle map photo on Monday. The pavillion side is on top and the crown side is at the bottom.

 

[strmrdr]

yea if it looks like that something is going on with the girdle.
either pavilion painting or digging depending on if its the mains or halves that are smaller.

 

[Rhino]

Hey gladstone,

Unfortunately features in girdle cutting such as digging/painting is not detectable with typical Sarin numbers.

Just curious what the date on the AGS Report is. BTW the description you give of the appearance is exactly what we observe as well. The majority of observers in GIA''s study found this to be an unappealing feature just as you and I do.

Regarding numbers from a Sarin/OGI, a knowledge of upper girdle angles/lower girdle angle relationships would help. When that''s not possible then a girdle graph certainly helps and what you''ve drawn seems to be the dead givaway.

 

[gladstone]

Here is my big fat girdle map. Is this digging considered as tweaking or cheating?

 

[CareBear]

gladstone, I''m not an expert on dug out girdles but a 6.9 mm for a 1.25 is not bad at all.

 

[gladstone]

Date: 8/26/2006 2:55:02 AM
Author: Rhino
Hey gladstone,

Unfortunately features in girdle cutting such as digging/painting is not detectable with typical Sarin numbers.

Just curious what the date on the AGS Report is. BTW the description you give of the appearance is exactly what we observe as well. The majority of observers in GIA''s study found this to be an unappealing feature just as you and I do.

Regarding numbers from a Sarin/OGI, a knowledge of upper girdle angles/lower girdle angle relationships would help. When that''s not possible then a girdle graph certainly helps and what you''ve drawn seems to be the dead givaway.

Rhino,

Thanks for your comment. The AGS report was issued late 2003. This was the old AGS system.

The stone is an above average performer except for the upper girdle facets which has no activity at all.

 

[Rhino]

Date: 8/28/2006 10:03:43 PM
Author: gladstone

Date: 8/26/2006 2:55:02 AM
Author: Rhino
Hey gladstone,

Unfortunately features in girdle cutting such as digging/painting is not detectable with typical Sarin numbers.

Just curious what the date on the AGS Report is. BTW the description you give of the appearance is exactly what we observe as well. The majority of observers in GIA''s study found this to be an unappealing feature just as you and I do.

Regarding numbers from a Sarin/OGI, a knowledge of upper girdle angles/lower girdle angle relationships would help. When that''s not possible then a girdle graph certainly helps and what you''ve drawn seems to be the dead givaway.

Rhino,

Thanks for your comment. The AGS report was issued late 2003. This was the old AGS system.

The stone is an above average performer except for the upper girdle facets which has no activity at all.

Hi Gladstone,

Yea ... that girdle graph (from an OGI) appears to be a stone that would not make it in either AGS or GIA''s current systems. One important reason IMO to either have a newer report or consult a gemologist/appraiser who is familiar with the degrees of painting/digging allowable in the new systems. Gladstone ... did you see the example of digging I had posted in this thread? Check out the Sarin numbers and the IdealScope image. Sir John was kind enough to rehash the thread with further commentary I had made on that one but it was a good example of digging similar to what you posted. That stone is one amongst a few in an upcoming video I''m working on demonstrating the visual differences between GIA Ex''s vs GIA VG''s.

Peace,

 

[gladstone]

The stone on the right (from Johnathan's thread) pretty much describe how my stone's outer facets look in day light. As much as 25% of the crown facets are dark. The stone doesn't appear round when you look at it from a distance.

I know this type of digging adversely influence light return performance and add weight. Does good Pricescope vendors here screen out stone like mine?

 

[gladstone]

More like this stone on the right. The last picture was not a fair comparision. This one has similar symmetry as my stone. But you get the idea. Excellent light return everywhere except these 16 little facets.

Picture credit goes to GOG's Rhino

 

[Rhino]

Hey gladstone,

Yes... that stone you posted in the last pic is in fact the stone I used in that example I posted the link to above. It''s also the stone I use in my own tutorial on digging and is an H&A stone (formerly an AGS Ideal under the old system). Not only do we observe exactly what you pointed out (around the 16 upper half facets) but I can even note a little more darkness under the table too in a side by side comparison of other GIA Ex''s. In older type certs these features were never taken into account.

It''s a shame it was never considered by the major labs before but both labs have made great strides to address these issues which do in fact impact face up appearance.

Good observations Watson.

Kind regards,

 

[gladstone]

Rhino,

Thank you for answering many of my questions.

I really wonder how the dug-out stone score on the BS and Isee2. In real life, I personally see that it''s not very desirable. Just wondering how the technology see it.

 

[Rhino]

Date: 8/31/2006 12:09:53 AM
Author: gladstone
Rhino,

Thank you for answering many of my questions.

I really wonder how the dug-out stone score on the BS and Isee2. In real life, I personally see that it's not very desirable. Just wondering how the technology see it.

Very good question gladstone. One of the limitations of the Bscope, Isee2, & red reflectors is their inability to detect the degrees of digging & painting that impact face up appearance which is why these are primary features we check for before we begin further testing on non GIA Ex stones. The best technologies for the job (short of a GIA Ex Report) are IMHO...

1. The GIA DiamondDock (as it allows the viewer to plainly see the optical effects of these features although it's certainly not limited to this viewing environment as you have duly noted)
2. Helium Report (particularly the latest installment showing azimuth deviation and notches/degrees of these features).
3. ASET imagery.
4. Girdle graphs from an OGI.
5. Detailed Sarin Reports which show the relationship of the girdle thickness from the mains to the half facets (which is visibly shown in the OGI girdle graph).
6. Sarin 3d model analysis of the girdle.

As you can see, some of these tools give numerical data, some visual. It is fun and challenging corellating the two especially noting how they appear to the average layman such as yourself which is why your observations interest me gladstone. Have a great day/evening depending where in the world you are.

Kindest regards,

 

[He Scores]

RE:I am shy to tell people that the stone is AGS ideal knowing that the cutter took advantage of the manner by which the lab measure the gridle thickness. I believe one of our stone is severely dug out by a cutter to gain weight.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


If the girdle bzls% is GREATER than the girdle hlvs% on the Sarin mfg. report, this is an indication that the halves were dug out, but it won''t tell you which ones, upper or lower.

For everyone''s edification, digging does not save weight, quite the opposite it LOSES weight because more material is taken away in the process. I addressed this in a counter article to AGS'' digging study.


Bill Bray
Diamond Cutter

 

[gladstone]

Date: 8/31/2006 9:25:16 AM
Author: He Scores
RE:I am shy to tell people that the stone is AGS ideal knowing that the cutter took advantage of the manner by which the lab measure the gridle thickness. I believe one of our stone is severely dug out by a cutter to gain weight.

~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~


If the girdle bzls% is GREATER than the girdle hlvs% on the Sarin mfg. report, this is an indication that the halves were dug out, but it won''t tell you which ones, upper or lower.

For everyone''s edification, digging does not save weight, quite the opposite it LOSES weight because more material is taken away in the process. I addressed this in a counter article to AGS'' digging study.


Bill Bray
Diamond Cutter

Bill,

Digging takes away material to mis-represent the girdle thickness and disguise weight. To cover up... that''s what I meant by digging to gain weight. It''s done to rip people off.

 

[He Scores]

Gladstone,

I''m sorry. I misunderstood what you were trying to convey.

You are absolutely correct....the drastic digging is an attempt to reduce the appearance of an otherwise thick girdle. If only done in certain areas it may have been done to reduce/remove natural material or flaws/chips.


Bill Bray
Diamond Cutter

 

[gladstone]

My fault. I have edited my original post to make it clearer.... I changed the word gain to hide.

" I believe one of our stone is severely dug out by the cutter to [hide] weight."