CVD Discoloration/UV light

[JayneClaire]

I recently selected a laboratory-grown GIA cert'd XXX with cut parameters that fall within the AGS0 range and find the stone to be beautiful. However, I came across some information that CVD grown diamonds may discolor reversibly and potentially irreversibly over time when exposed to UV light. Is that a concern I need to worry about? The GIA is a "dossier" which apparently doesn't contain the growth method, only that the diamond is "man-made." The jeweler says it's CVD. Any suggestions? I would like to keep this stone because it has great fire and is well cut but I am going to set it in a bezel with other diamonds and certainly do not want to have to remove it if it becomes discolored over time.

 

[mayaINaU]

I recently selected a laboratory-grown GIA cert'd XXX with cut parameters that fall within the AGS0 range and find the stone to be beautiful. However, I came across some information that CVD grown diamonds may discolor reversibly and potentially irreversibly over time when exposed to UV light. Is that a concern I need to worry about? The GIA is a "dossier" which apparently doesn't contain the growth method, only that the diamond is "man-made." The jeweler says it's CVD. Any suggestions? I would like to keep this stone because it has great fire and is well cut but I am going to set it in a bezel with other diamonds and certainly do not want to have to remove it if it becomes discolored over time.

I read this article after I bought a CVD and it seems like it’s a rare and temporary change, and would not happen if there were post-growth treatment applied to the CVD diamond, which stabilizes the color. https://www.jckonline.com/editorial-article/lab-grown-diamonds-change-color/

 

[Texas Leaguer]

I wouldn't worry too much about it. The article makes clear that this issue is quite rare. And it is common for CVD grown stones to be HPHT treated which also helps to stabilize them.

CVD grown diamonds have some unique properties. They are grown in a low pressure environment ( weird, right!). And the machines have windows on them that allow the operator to visually monitor the process. Some defects such as color tinges result from non-carbon trace elements in the reactor. Silicon atoms are mentioned in this article as possibly accounting for this color changing phenomenon. They are leached into the chamber from the glass window!

The presence of the window also allows the operator to see an issue developing and to stop the process to correct the problem. But starting and stopping the process introduces fluctuations that can result in striation in the carbon lattice. If too pronounced, striation can cause a transparency deficit, resulting in the stone being slightly hazy.

Because CVD reactors are so much smaller, lighter and less expensive that the huge presses used in the HPHT process, there are many more of them in service. So there is greater variation in the level of experience and expertise of the CVD grower community.

 

[Karl_K]

It says its short wave UV which a stone will only see at very high levels in a diamond tester.
When we think of UV and diamonds as graded on the reports and the effects seen in person is long wave UV.
Most if not nearly all lab diamonds are inert under long wave UV.

 

[Texas Leaguer]

It says its short wave UV which a stone will only see at very high levels in a diamond tester.
When we think of UV and diamonds as graded on the reports and the effects seen in person is long wave UV.
Most if not nearly all lab diamonds are inert under long wave UV.

Yes, this is an important point for the poster. Even if the diamond has this color change property, it is unlikely to ever get activated in real life.

 

[glitterata]

That sounds really cool. I'd love to have a stone like that.

 

[JayneClaire]

All of your comments and clarifications are extremely helpful and very much appreciated! I will enjoy the diamond and I hope everyone has a happy holiday season!

 

[oncrutchesrightnow]

First person to bring to market diamonds that reliably and reversible change color to violet/blue will make a lot of money.