Pink Topaz from collector...

[cofor]

Anyone here knows if the diffusion treated or coated pink topaz shows any pronounced dicroism?
Got one from a collector who claims it is heat treated. It shows dicroism very sharply. One ray is more salmonish pink (with a orangish yellow overtone) the other is more purplish pink. It also shows faint color zoning or banding under crossed polars.
No coating has been detected.

Conny

 

[T L]

Date: 2/17/2009 2:47:00 PM
Author:cofor
Anyone here knows if the diffusion treated or coated pink topaz shows any pronounced dicroism?
Got one from a collector who claims it is heat treated. It shows dicroism very sharply. One ray is more salmonish pink (with a orangish yellow overtone) the other is more purplish pink. It also shows faint color zoning or banding under crossed polars.
No coating has been detected.

Conny

I don't know about diffusion treated topaz, but coated topaz is simply white topaz with a coating over it. I could be wrong, but common sense would tell me that there is no dichroism.

Do you have a picture you can upload?

 

[cofor]

I have no image right now and it is getting late here in scandinavia. Will try to get one uploaded during this week. Maybe both daylight and incandescent. Anyhow I will recut the stone as it is "native" cut and has a disturbing window in the center. After that we will know for sure if it was diffused

.

Conny

 

[coatimundi_org]

Hiya Conny-
Regular heat treated pink topaz may show moderate dichroism. You think it''s diffused because of the strong dichroism?

I''m very interested in hearing what you find while faceting. Pics!

 

[chrono]

Very interesting; I've never heard of pink topaz having dichroism. I'm interested in the answer because I'm in the process of getting a pink topaz myself but I believe mine to be unheated and untreated.

 

[coatimundi_org]

Hi Chrono--I''ve only seen dichroism in pink topaz through a dichroscope. Any untreated pink topaz I''ve seen did not display eye visible pleo. Untreated pink topaz is very pretty--now I want a piece!

 

[chrono]

That''s excellent news, Coati. Thanks!

 

[cofor]

Maybe some clarification. The pronounced dichroism I detect is also seen through the dicroscope. Weakly seen with naked eye.
No I did not think a diffused stone would be strongly dichroic, rather the opposite. That is why I am asking.
I have never seen any diffused Topaz irl AFAIK.

Images will come later on. I have a busy time at work so it is usually dark when I get home an I would like to make some comparative images in daylight.

 

[coatimundi_org]

I''ve never seen diffused topaz either. Looking forward to your pics!

 

[cofor]

The topaz in incandescent light.

 

[chrono]

Is the colour in the picture accurate? I'd almost call it diffused right away! I've seen light and dark pink topazes but not one like that. Amazing!

 

[cofor]

The image is close to the real color. It''s a bit more "salmony" (orange overtones) when looked at with naked eye. In daylight the color is more purplish. Will try to get the time to take some daylight shots today or tomorrow.

 

[T L]

Here''s a picture of a mineral specimen of a very pinkish purplish pink topaz on youtube. You can view this on youtube (I left the title in there).

 

[DiamanteBlu]

Wow! What great colors! Now I want one too!

 

[chrono]

Great looking pink!

That one''s worth collecting.

 

[cofor]

Here is a more "color true" incandescent light image.

 

[Lorelei]

Gorgeous pink!!

 

[cofor]

And here comes a daylight image. It is slightly more bluish than in reality.

 

[mochi]

It''s beautiful!

 

[NeverEndingUpgrade]

Gorgeous stone, but what in the world are you guys talking about?!?

 

[Lorelei]

It really is a pretty stone!

 

[cofor]

Actually we are talking about what treatment is likely to have been done to this stone. It is said to be heat treated only but I suspect radiation or diffusion treatment.
It is no doubt Topaz. The origin is said to be Brazilian but as the stone has no inclusions big enough to be of any help regarding origin it could originate from any topaz bearing country. At least I'm sure it is not coated.

 

[T L]

Date: 3/1/2009 9:55:46 AM
Author: cofor
Actually we are talking about what treatment is likely to have been done to this stone. It is said to be heat treated only but I suspect radiation or diffusion treatment.
It is no doubt Topaz. The origin is said to be Brazilian but as the stone has no inclusions big enough to be of any help regarding origin it could originate from any topaz bearing country. At least I''m sure it is not coated.

Unless you send it to a reputable lab, there really is no way to tell if it''s been irradiated. I posted the picture of the mineral specimen above because topaz in a similar color to your cut gem does exist in nature. Unfortunately, topaz is one of the most widely treated gems, so I suggest you get it checked out by a lab if you want to know for sure. It may or may not be worth it based on the expense of the report.

 

[cofor]

Thanks TL, I am aware of the need for a lab report to detect radiation. I will make a recut of the stone and after that I might consider sending it to a lab. Depends of the outcome. If the stone is surface diffused it will probably loose most of the color during recutting.