Ummmm.....how does an AGS graded diamond earn its zero?

[Regular Guy]

Basically....for at least part of the analysis, reviewed today my JP, the review of the diamond is graphical, so...

"At AGSL the whole diamond is scanned and ray-traced in 3D, so leakage will cause it to take a hit in brightness...."

but, how does the graphical analysis turn back into a number (0). That is...are maybe 90 scans taken, some defintion of "yes" or 'no" somehow assigned to each of the scans...and then...if like 75 out of 90 get a yes...that produces an OK for that part of the analysis towards getting a zero. This...just for the light performance part. I guess there are 11 components that go into the analysis...so let's just focus on this one part.

Somehow...the pictures get to numbers, right?

Separately, relatedly, how can a diamond with the proportions of table 56.8, depth 62, crown 34.9 and pavilion of 41.2...just any random diamond with those proportions...end up getting the zero?

Many thanks!

 

[strmrdr]

There are many things that go into it and they arent exactly public info.

From looking at the AGS software output one of the main ones is the ratio of black, blue, red and green in the aset as well as its distribution.
I suspect they break the diamond up into at least 3 zones.
table, bezels and stars, upper girdles.

 

[strmrdr]

Date: 3/10/2009 11:20:09 AM
Author:Regular Guy
Separately, relatedly, how can a diamond with the proportions of table 56.8, depth 62, crown 34.9 and pavilion of 41.2...just any random diamond with those proportions...end up getting the zero?


Many thanks!

Here is one way to get that combo into a 0 maybe a 1

 

[strmrdr]

another way with shorter lgf%

 

[strmrdr]

yet another way...
When Andrey finds time to get my article up this will become clear what is going on here.

 

[Regular Guy]

Date: 3/10/2009 12:06:18 PM
Author: strmrdr

Date: 3/10/2009 11:20:09 AM
Author:Regular Guy
Separately, relatedly, how can a diamond with the proportions of table 56.8, depth 62, crown 34.9 and pavilion of 41.2...just any random diamond with those proportions...end up getting the zero?


Many thanks!

Here is one way to get that combo into a 0 maybe a 1

Given these 3 cases...I wonder how extreme would be such a manipulation for any such diamond, to produce the result you''ve described.

That is...let''s presume the zero accurately describes the resulting diamond, in terms of valued light performance. Can you characterize if extreme measures particularly were engaged to get the result?

Put a different way...to what extent does a mere proportions based evaluative system (GIA, HCA, AGA) tell us too little about performance to give any of them much consideration....

 

[strmrdr]

proportions based evaluative systems are rejection tools not acceptance tools.
AGS 3D is a borderline acceptance tool but I would like images to make sure.

As far as how extreme they are the first 2 have pavilion painting which has a bad rap and the third would have large clefts in the hearts and turn off some h&a proponents.
All 3 would be an improvement over the original combo.
The biggest problem with these fringe combos is that a sarin scan can give a false picture of what they actually are when used as a base for a 3d model.
garbage in garbage out.
Helium scans as input into the 3d system would be able to sort them correctly with acceptable accuracy.
So if you see one with a ags0 on the report, is it good or not?
No way to tell without images,,,

 

[strmrdr]

here is the article:
http://journal.pricescope.com/Articles/68/1/Do-the-pavilion-mains-drive-light-return-in-the-modern-round-brilliant.aspx