An AGS0 with a Bad Idealscope image

[Lklucky]

I was super interested in this stone until I requested an idealscope and saw this, didn't know this was possible on an AGS 0 you may need to click on idealscope iconhttp://www.exceldiamonds.com/Diamon...nd-1-85-Carat-H-Color-VS2-Clarity-265350.html

 

[Dreamer_D]

I can't read the lab report, what are the crown, table, CA and PA?

 

[yssie]

They happen! AGS0 tells you that the stone is AGS0... you still need to do your due diligence to determine whether the stone satisfies your requirements since AGSL isn't issuing cut grades according to your requirements



AGS#: 104063526006
Report Type: The Platinum Light Performance Diamond Quality® Document
Shape and Style: Round Brilliant
Measurements: 7.83 - 7.86 x 4.91 mm
Cut Grade: AGS Ideal 0
Color Grade: AGS 2.0 (H)
Clarity Grade: AGS 4 (VS2)
Carat Weight 1.858
Fluorescence: Negligible
Comments:

"AGSL 104063526006" has been inscribed on the girdle of this diamond.
Additional clouds are not shown.

Polish: Ideal
Symmetry: Ideal
Table: 56.2%
Crown Angle: 35.8
Crown Height: 15.7%
Girdle: Faceted, 1.7% to 3.8%
Pavilion Angle: 40.9
Pavilion Depth: 43.2%
Star Length: 49%
Lower Girdle Length: 79%
Total Depth: 62.5%
Culet: Pointed

 

[Lklucky]

AGS#:   104063526006
Report Type:   The Platinum Light Performance Diamond Quality® Document
Shape and Style:   Round Brilliant
Measurements:   7.83 - 7.86 x 4.91 mm
Cut Grade:   AGS Ideal 0
Color Grade:   AGS 2.0 (H)
Clarity Grade:   AGS 4 (VS2)
Carat Weight   1.858
Fluorescence:   none


Light Performance:   0
Polish:   Ideal
Symmetry:   Ideal
Table:   56.2%
Crown Angle:   35.8
Crown Height:   15.7%
Girdle:   Faceted, 1.7% to 3.8%
Pavilion Angle:   40.9
Pavilion Depth:   43.2%
Star Length:   49%
Lower Girdle Length:   79%
Total Depth:   62.5%
Culet:   Pointed

 

[Lklucky]

I thought no obvious light leakage was a requirement for an AGS0 and for that matter most anyone's requirement.

 

[yssie]

I thought no obvious light leakage was a requirement for an AGS0 and for that matter most anyone's requirement.

Obviously not.

It is, in general, the probable outcome of AGSL's grading process - making AGS0 RBs the "safest" bets if one is going to buy blind and one values ISs that are blood red under the table (like most PSers), but it's not a guarantee.

http://www.americangemsociety.org/performancegradingso

 

[Draco]

I was super interested in this stone until I requested an idealscope and saw this, didn't know this was possible on an AGS 0 you may need to click on idealscope iconhttp://www.exceldiamonds.com/Diamon...nd-1-85-Carat-H-Color-VS2-Clarity-265350.html

That is a badly taken Idealscope image, diamond is tilted see the generated ASET.
The AGS report is here and looks fine, the proportions also look fine and would not likely cause so much leakage.

Ask the vendor to retake the idealscope image.

http://www.agslab.com/pdf_sync_reports/104063526006-PLDQR.PDF

 

[yssie]

I was super interested in this stone until I requested an idealscope and saw this, didn't know this was possible on an AGS 0 you may need to click on idealscope iconhttp://www.exceldiamonds.com/Diamon...nd-1-85-Carat-H-Color-VS2-Clarity-265350.html

That is a badly taken Idealscope image, diamond is tilted see the generated ASET.
The AGS report is here and looks fine, the proportions also look fine and would not likely cause so much leakage.

Ask the vendor to retake the idealscope image.

http://www.agslab.com/pdf_sync_reports/104063526006-PLDQR.PDF

Diamond is very slightly tilted, will not account for the majority of light escape pic shows - also IMO will not satisfy those PSers who do value "no leakage under the table". Nothing to suggest pic was improperly taken otherwise. Looks like IS pic/actual pic/report match.

 

[partgypsy]

What's weird is that if you type in the specs in the HCA (using crown and pavillon angles) not only does it get a score of 4, according to where it lands it is outside the AGS 0 parameters. So I'm not sure how it got an "ideal" cut grade from AGS.

 

[yssie]

What's weird is that if you type in the specs in the HCA (using crown and pavillon angles) not only does it get a score of 4, according to where it lands it is outside the AGS 0 parameters. So I'm not sure how it got an "ideal" cut grade from AGS.

I *believe* Garry based them off the proportions charts?
AGSL assigns grades entirely by PGS output so a stone that performs well in their grading software - by whatever requirements/metrics, I don't know enough about it to guess - can get the 0 grade even if proportions fall outside the ID range on the proportions charts. They don't consider the effects of colour/inclusions either.

 

[Lklucky]

Yeah and this is what I have been discovering as well, almost all of the AGS0 I have tried in the HCA advisor have scored well over 2, I ended up having to see one in person to see that it indeed was great with light and scintillation, the one my fiancé and I ended up buying scored a 2.5 on the HCA but was brilliant in person. (it had a great idealscope as well)

 

[yssie]

Yeah and this is what I have been discovering as well, almost all of the AGS0 I have tried in the HCA advisor have scored well over 2, I ended up having to see one in person to see that it indeed was great with light and scintillation, the one my fiancé and I ended up buying scored a 2.5 on the HCA but was brilliant in person. (it had a great idealscope as well)

Yup HCA is a weeding tool, it doesn't consider a number of proportions factors or optical symmetry - which makes it efficient and easy to use! But also means that there are definitely beautiful stones that "fail". Congrats on finding your stone

 

[Lklucky]

Yeah and this is what I have been discovering as well, almost all of the AGS0 I have tried in the HCA advisor have scored well over 2, I ended up having to see one in person to see that it indeed was great with light and scintillation, the one my fiancé and I ended up buying scored a 2.5 on the HCA but was brilliant in person. (it had a great idealscope as well)

Yup HCA is a weeding tool, it doesn't consider a number of proportions factors or optical symmetry - which makes it efficient and easy to use! But also means that there are definitely beautiful stones that "fail". Congrats on finding your stone

Thank you, I'm excited and now the search for a setting starts!

 

[Laila619]

It happens! I've seen it before.

 

[Karl_K]

The image on the ags report and the grade is based on scan data then computer generated.
In this case scanner error made this diamond appear to the software better than it really is based on the IS image.
That is why it is always a good idea to get real images and double check.

 

[partgypsy]

What do you mean by scanner error?

 

[yssie]

What do you mean by scanner error?

Not Karl obviously, but stones are scanned and the results inputted into AGSL's PGS/used by GIA to determine cut grade w/ proportions charts. Scanners don't map the external contours of the stone w/ complete accuracy - some are better than others.

Old article - probably out of date in terms of scanner specs but it highlights some of the issues you can run into w/ relying solely on the simulated ASET on the DQD http://www.goodoldgold.com/content.php?c=103

 

[diamondloveaffair]

what is the tolerance and amount of error for the type of scanners used at AGS?

 

[Karl_K]

what is the tolerance and amount of error for the type of scanners used at AGS?

under perfect conditions rated at +/- .1 degree. (who believes manufacturer ratings?)
http://www.sarin.com/diamensionhd.asp
The problem is in the real world conditions are rarely perfect, at this level a little spec of dust can throw things off way more than that.