Brown facets in RB?

[Bunnifer]

Can anyone describe what the brown stuff is on the facets? I can only describe it as if the diamond were rubbed in dirt and then wiped off...



Here is the link to the diamond...
http://www.jamesallen.com/diamond.asp?b=16&a=12&c=77&cid=131&item=945305

 

[kenny]

If AGS gave it an H the overall color could not be this brown.

Must be the white balance in their camera is not set correctly, or some other step in the photo/electronic process.

Are you refering to the overall color or the dark shadow outlinine some of the brighter facets?

 

[Bunnifer]

I didn''t think it should be this brown either since it is an H. But I couldn''t help wondering...

You''re probably right, Kenny -- it''s probably the camera and not the diamond.

 

[DBM]

there''s just a glitch with the pic. you can even see that the inner "star design" is whiter than the outer, like two different pics.

 

[Bunnifer]

Date: 11/28/2006 11:50:34 AM
Author: kenny
If AGS gave it an H the overall color could not be this brown.


Must be the white balance in their camera is not set correctly, or some other step in the photo/electronic process.


Are you refering to the overall color or the dark shadow outlinine some of the brighter facets?

I''m referring to the dark shadow outlining some of the brigher facets. I found a couple of diamonds on the JA website which also exibit this characteristic.

So, this doesn''t have anything to do with the color/clarity of the diamond but is more of a photographic issue? Nevertheless, I think it makes the diamonds look bad...

 

[oldminer]

The "brown" is a reflection of either the lens of the camera or the long hair of the photographer (brown hair). I doubt it is anything but an artifact of the image, not in the diamond.

 

[Cehrabehra]

Date: 12/5/2006 4:10:13 PM
Author: Bunnifer

Date: 11/28/2006 11:50:34 AM
Author: kenny
If AGS gave it an H the overall color could not be this brown.


Must be the white balance in their camera is not set correctly, or some other step in the photo/electronic process.


Are you refering to the overall color or the dark shadow outlinine some of the brighter facets?

I''m referring to the dark shadow outlining some of the brigher facets. I found a couple of diamonds on the JA website which also exibit this characteristic.

So, this doesn''t have anything to do with the color/clarity of the diamond but is more of a photographic issue? Nevertheless, I think it makes the diamonds look bad...

I DON''T oop think it is the camera OR the color/clarity - I suspect it is a bit of something like a kozibe effect... sort of... it''s not replicating the culet in the crown facets, but it is reflecting one of the dark shadows from the camera.... I don''t know how to explain it, but I think it''s reflecting shadows from the camera.

 

[Cehrabehra]

Date: 12/5/2006 4:14:45 PM
Author: oldminer
The ''brown'' is a reflection of either the lens of the camera or the long hair of the photographer (brown hair). I doubt it is anything but an artifact of the image, not in the diamond.

ha! hehe.... but do you think it could be an indication of a poor cut if it''s reflecting part of the "arrows" up there like that?

 

[CaptAubrey]

I agree with Dave--the diamond is picking up brown from something brown-colored in the vicinity.

Brown is not a spectral color and so could not be created by the light being refracted around the stone.

 

[Garry H (Cut Nut)]

I too agree.

I have spent some time modelling this diamond with ray tracing and it seems likely that the leakage is going directly behind the stone as in this image.

There is also a 2nd unlikely possability - sometimes light from certain directions bounces around inside a stone until it completely disapates -this is one of the tricks the colored diamond cutters aim for - it exaggerates the color of the diamond and reduces the brilliance and contrast - all aims or a colored cutter.

 

[Garry H (Cut Nut)]

The 2nd unlikely possability I mentioned above - sometimes light from certain directions bounces around inside a stone until it completely disapates -this is one of the tricks the colored diamond cutters aim for - it exaggerates the color of the diamond and reduces the brilliance and contrast - all aims or a colored cutter.

 

[Bunnifer]

Date: 12/5/2006 6:29:22 PM
Author: Garry H (Cut Nut)
I too agree.


I have spent some time modelling this diamond with ray tracing and it seems likely that the leakage is going directly behind the stone as in this image.


There is also a 2nd unlikely possability - sometimes light from certain directions bounces around inside a stone until it completely disapates -this is one of the tricks the colored diamond cutters aim for - it exaggerates the color of the diamond and reduces the brilliance and contrast - all aims or a colored cutter.

Interesting...the AGS cert says that this is an AGS000 diamond...should there be leakage like this in an AGS000?

 

[JulieN]

Date: 12/5/2006 10:10:35 PM
Author: Bunnifer

Interesting...the AGS cert says that this is an AGS000 diamond...should there be leakage like this in an AGS000?

It's fine. The brown places aren't where the "problem" leakage occurs.

 

[Garry H (Cut Nut)]

Date: 12/5/2006 10:10:35 PM
Author: Bunnifer


Interesting...the AGS cert says that this is an AGS000 diamond...should there be leakage like this in an AGS000?

all diamond have leakage.
For example one method aGS use has a result of 12.9% leakage for an AGS 0 stone. But this is not an absolute number - it is an indication only.

When we look at the star in the center of a Tolkowsky diamond like the stone pictured above - about 17% of the light falling on the diamond is reflected off the surface and 67$ refracted back out the top = 84% returned and 16% lost to leakage.

 

[Bunnifer]

Date: 12/5/2006 11:09:52 PM
Author: Garry H (Cut Nut)

Date: 12/5/2006 10:10:35 PM

all diamond have leakage.

For example one method aGS use has a result of 12.9% leakage for an AGS 0 stone. But this is not an absolute number - it is an indication only.


When we look at the star in the center of a Tolkowsky diamond like the stone pictured above - about 17% of the light falling on the diamond is reflected off the surface and 67$ refracted back out the top = 84% returned and 16% lost to leakage.

Oh, OK. So, just out of curiosity, would it be accurate to say that a well-cut diamond depends on percentage of light leakage? If so, would it be accurate to say that the less light leakage, the better the cut?