Does HPHT color treatment on diamonds destry fluorescence?

[T L]

Just curious if it does, or if it does to some extent.

 

[LD]

I don''t think it does TL. Some of my irradiated coloured diamonds fluoresce.

 

[T L]

LD,
Those are irradiated though. I''m talking high temperature high pressure treatement which drives off brown and some other unwanted tones on diamonds.

 

[LD]

I need to go back to my books!!!! I thought the two processes were the same?

I've read this:

"The diamond grading labs are perfecting ways to detect the HPHT diamond color treatment so that consumers can receive full disclosure about the diamonds they purchase. If HPHT diamond color treatments are detected, Gemological Institute of America (GIA) grading reports now state "HPHT Annealed" or "Artificially Irradiated" in the Origin of Color portion of a report. Only HPHT color treated diamonds that are laser-inscribed with the words "HPHT PROCESSED," "IRRADIATED," or a specific registered name (GE for example) are fully graded by GIA."

 

[T L]

Date: 11/2/2009 6:46:33 PM
Author: LovingDiamonds
I need to go back to my books!!!! I thought the two processes were the same?

I''ve read this:

''The diamond grading labs are perfecting ways to detect the HPHT diamond color treatment so that consumers can receive full disclosure about the diamonds they purchase. If HPHT diamond color treatments are detected, Gemological Institute of America (GIA) grading reports now state ''HPHT Annealed'' or ''Artificially Irradiated'' in the Origin of Color portion of a report. Only HPHT color treated diamonds that are laser-inscribed with the words ''HPHT PROCESSED,'' ''IRRADIATED,'' or a specific registered name (GE for example) are fully graded by GIA.''

Thanks LD for that. I have heard that some unscrupulous sellers will polish away the laser inscription and sell the HPHT diamond as natural color. I''m also wondering what colors are typically HPHT treated and what the resulting colors typically are.

 

[T L]

bump!

 

[Michael Marcel]

TL. HTHP diamonds do not lose their fluorescence as a rule, no. There are two major categories of HTHP diamonds. First, those that were originally brownish (or otherwise undesirably) colored and then treated with HTHP to become colorless white diamonds. These specimens would certainly lose fluorescent qualities in becoming colorless.

However, the newer and more valuable category of HTHP diamonds are those diamonds which start out light brown (or an otherwise undesirable) color and go through the HTHP treatment to become dazzling COLOR TREATED NATURAL DIAMONDS. These natural diamonds of enhanced color have reached their potential becoming nearly any shade in the rainbow including yellow, pink and many other colors.

In such cases, the diamonds have not lost any fluorescent qualities--on the contrary, these diamonds have increased fluorescence due to proper HTHP treatment!
-Hope that helps-

Michael

 

[Garry H (Cut Nut)]

Date: 11/26/2009 2:53:31 AM
Author: Michael Marcel
TL. HTHP diamonds do not lose their fluorescence as a rule, no. There are two major categories of HTHP diamonds. First, those that were originally brownish (or otherwise undesirably) colored and then treated with HTHP to become colorless white diamonds. These specimens would certainly lose fluorescent qualities in becoming colorless.

However, the newer and more valuable category of HTHP diamonds are those diamonds which start out light brown (or an otherwise undesirable) color and go through the HTHP treatment to become dazzling COLOR TREATED NATURAL DIAMONDS. These natural diamonds of enhanced color have reached their potential becoming nearly any shade in the rainbow including yellow, pink and many other colors.

In such cases, the diamonds have not lost any fluorescent qualities--on the contrary, these diamonds have increased fluorescence due to proper HTHP treatment!
-Hope that helps-

Michael

True - some of the most amazing fluoro green/yellow stones I ever saw came out of some browns I snt to a lab in Prague as an experiment. They popped!!!!