Rhino or anybody with a diamCalc help me with this RB ? ...thanks

[Dancing Fire]

would like to see how it looks on diamcalc.

Measurements: 6.80 x 6.82 x 4.14
Crown angle: 34.1 height: 14.9
PAV angle: 40.8 depth: 42.9
Table: 56%
total depth: 60.9
girdle: 1.2-1.5%

 

[Garry H (Cut Nut)]

There are many Diamcalc''s you can find with these parameters with a simple search.

If you want something worth looking at - get us the .srn sarin 3D file from DiaVision

 

[Dancing Fire]

Date: 12/23/2004 3

7

6 AM
Author: Garry H (Cut Nut)
There are many Diamcalc''s you can find with these parameters with a simple search.

If you want something worth looking at - get us the .srn sarin 3D file from DiaVision

cut nut

i don''t have the 3D file from DiaVision.i thought all you need is the specs to do the calculation....no ?

 

[Garry H (Cut Nut)]

It will make a pretty ideal-scope image but will not convey the symmtry and other stuff.
It can mislead you - none of us with DiamCalc will do this without a 3D file anymore.

Run it on HCA

 

[Rhino]

Date: 12/23/2004 5:11:13 AM
Author: Garry H (Cut Nut)
It will make a pretty ideal-scope image but will not convey the symmtry and other stuff.
It can mislead you - none of us with DiamCalc will do this without a 3D file anymore.

Run it on HCA

Gary I can completely understand why you say this. There are many things that a generic DiamCalc model can not imitate which you can get from an actual scan/3d model. These 2 images below are generated in DiamCalc based on proportion data you've given but since we do not know a. variances and b. star facet, lower girdle, upper girdle data you can have a stone that is either of these or falls somewhere in between. Again ... DiamCalc is showing perfect optical symmetry while in real life it is most likely not like this at all.

Also, the 2 examples below are going to appear different depending upon the light source it is observed under. One will have greater DCLR than the other.

All the best,

 

[Dancing Fire]

Rhino
thanks, for the pictures.i guess my stone looks more like the one on the right under the I-scope it has the skinnier arrows.

at what point does a stone consider a shallow/shallow combo ?

 

[Rhino]

Date: 12/23/2004 7:16:12 PM
Author: Dancing Fire
Rhino
thanks, for the pictures.i guess my stone looks more like the one on the right under the I-scope it has the skinnier arrows.

at what point does a stone consider a shallow/shallow combo ?

My pleasure DF. If you''re talking about the stone you got from us, yes it is virtually identical to the 2nd image and is of the longer star/lower girdle combo (my favs).

Regarding shallow/shallow combo''s (diamonds in which head obstruction becomes a problem) ... you know from studying our site that alot of stones we feature have crown angles in the 34-34.5 range coupled with pavilion angles in the 40.7-40.9 range. As we''re testing and observing these we''ve been noting a declination in optical grading in diffuse light conditions as the pavilion angles get shallower than 40.7 ... ie. 40.6 and under. This can of course be compensated with steeper crown angles but I have not yet tested enough stones to arrive at concrete conclusions to determine how steep the crown angles must be to compensate. Recently we had called in a stone and on the AGS Report it had listed angles of 40.7 pavilion angles, 34.8 crown angles and a 56 table. However once the stone got here our Sarin measured it with the following angles.

 

[Rhino]

So I run the stone multiple times to see if perhaps there was dust on my stone or something but no... the pavilion angle measurement on the AGS was wrong. (I can also double check on the OGI as well). Anyhow ... here is the Isee2 on that same stone. In diffuse lighting and comparing to others with known higher Isee2 scores you could see that the balance of contrast was off in this one. In direct lighting the stone was awesome, in diffuse lighting it wasn't the best performer although it wasn't a terrible stone either.

 

[Dancing Fire]

Date: 12/23/2004 8:46

6 PM
Author: Rhino

Date: 12/23/2004 7:16:12 PM
Author: Dancing Fire
Rhino
thanks, for the pictures.i guess my stone looks more like the one on the right under the I-scope it has the skinnier arrows.

at what point does a stone consider a shallow/shallow combo ?

My pleasure DF. If you''re talking about the stone you got from us, yes it is virtually identical to the 2nd image and is of the longer star/lower girdle combo (my favs).

Regarding shallow/shallow combo''s (diamonds in which head obstruction becomes a problem) ... you know from studying our site that alot of stones we feature have crown angles in the 34-34.5 range coupled with pavilion angles in the 40.7-40.9 range. As we''re testing and observing these we''ve been noting a declination in optical grading in diffuse light conditions as the pavilion angles get shallower than 40.7 ... ie. 40.6 and under. This can of course be compensated with steeper crown angles but I have not yet tested enough stones to arrive at concrete conclusions to determine how steep the crown angles must be to compensate. Recently we had called in a stone and on the AGS Report it had listed angles of 40.7 pavilion angles, 34.8 crown angles and a 56 table. However once the stone got here our Sarin measured it with the following angles.

Rhino,
Actually the stone in question is the recut by Paul of Infinity Diamond. Is the 1.15 ct. I''m just using the measurements off of the AGS Cert.

About the above diamond that you tested, isn''t it kinda weird with all the other porportions matching the AGS Cert but the pav angle is different ? You must have one of those cheaper modle Sarin machine.....LOL J/K

 

[Rhino]

Date: 12/23/2004 9:13

2 PM
Author: Dancing Fire

Date: 12/23/2004 8:46

6 PM
Author: Rhino

Date: 12/23/2004 7:16:12 PM
Author: Dancing Fire
Rhino
thanks, for the pictures.i guess my stone looks more like the one on the right under the I-scope it has the skinnier arrows.

at what point does a stone consider a shallow/shallow combo ?

My pleasure DF. If you''re talking about the stone you got from us, yes it is virtually identical to the 2nd image and is of the longer star/lower girdle combo (my favs).

Regarding shallow/shallow combo''s (diamonds in which head obstruction becomes a problem) ... you know from studying our site that alot of stones we feature have crown angles in the 34-34.5 range coupled with pavilion angles in the 40.7-40.9 range. As we''re testing and observing these we''ve been noting a declination in optical grading in diffuse light conditions as the pavilion angles get shallower than 40.7 ... ie. 40.6 and under. This can of course be compensated with steeper crown angles but I have not yet tested enough stones to arrive at concrete conclusions to determine how steep the crown angles must be to compensate. Recently we had called in a stone and on the AGS Report it had listed angles of 40.7 pavilion angles, 34.8 crown angles and a 56 table. However once the stone got here our Sarin measured it with the following angles.

Rhino,
Actually the stone in question is the recut by Paul of Infinity Diamond. Is the 1.15 ct. I''m just using the measurements off of the AGS Cert.

About the above diamond that you tested, isn''t it kinda weird with all the other porportions matching the AGS Cert but the pav angle is different ? You must have one of those cheaper modle Sarin machine.....LOL J/K

Generally the AGS measurements are right on. I do catch them in mistakes from time to time though.

I was *very* puzzled when we were running the optical tests on this stone becuase none of the results were correlating with what we typically see with 34.8/40.7 combos. After much suspicion we checked the angles and sure enough ... we found the pavilion angle was not as it was presented on the AGS Report.

Paul cuts (or has cut for him) very nice stones. I don''t know the exact minor facet measurements so I can''t tell you exactly where it falls in the grand scheme of things but he does get those angles right and he is a perfect gentleman.

 

[Garry H (Cut Nut)]

Date: 12/23/2004 8:46

6 PM
Author: Rhino

Date: 12/23/2004 7:16:12 PM
Author: Dancing Fire
Rhino
thanks, for the pictures.i guess my stone looks more like the one on the right under the I-scope it has the skinnier arrows.

at what point does a stone consider a shallow/shallow combo ?

Regarding shallow/shallow combo''s (diamonds in which head obstruction becomes a problem) ... you know from studying our site that alot of stones we feature have crown angles in the 34-34.5 range coupled with pavilion angles in the 40.7-40.9 range. As we''re testing and observing these we''ve been noting a declination in optical grading in diffuse light conditions as the pavilion angles get shallower than 40.7 ... ie. 40.6 and under. This can of course be compensated with steeper crown angles but I have not yet tested enough stones to arrive at concrete conclusions to determine how steep the crown angles must be to compensate.

Rhino multiply the variation in pavilion angle from one you favour, by 5x and add or subtract it (inverse proportion) to the crown angle from your prefered model.

EG you like 34.5C and 40.7P - but you have a stone with 40.2 - the difference is 0.5 X 5 = 2.5.
34.5 + 2.5 = 37 degrees is the ideal crown angle.

Or 41P +0.3 x 5 = 1.5.
34.5 - 1.5 = 33 ideal crown angle.

Jasper showed it from Tolkowsky''s work - but the ideal table was bigger and the pavilion angle was shallower when accounting for math rounding errors. http://www.folds.net/diamond_girdle/index.html

My take on this can be read here http://www.diamond-cut.com.au/03_inverse_relationship.htm