Re: Radioactive Gemstones

["Barry Searle" <B.Searle@unsw.edu.au>]

Gemstones,

Out of interest, some years ago now, when I was operating an XRF unit I
placed some zircons and diamonds inside on top a an aperture and irradiated
them with x-rays (50kV, 20 nA)

Some good yellows colours occurred.

Quite safe etc,


Barry
EM UNIT
UNSW


-----Original Message-----
From: Ron L. Kathren <rkathren@tricity.WSU.edu>
To: Multiple recipients of list <radsafe@romulus.ehs.uiuc.edu>
Date: Monday, 30 November 1998 14:30
Subject: Re: Radioactive Gemstones


>In response to your questions:
>
>1.  Irradiation produces stable color centers (eg F centers) in the
>crystalline lattice of the gemstone.
>
>2.  You have described the basic technique.
>
>3.  The regulations that generally apply to use of radiation sources apply.
>
>Ron Kathren
>
>
> At 04:54 AM 11/28/98 -0600, Khalid Aleissa wrote:
>>Greeting to all RADSAFErs
>>I feel that the issue I'm about to post may not be posted for the first
>>time, therefore, I need you to patient and support me with what you know
>>about it. I know that some of the gemstones are exposed to high doses of
>>gamma rays or electron beams to induce or change their colors, I do not
>>have a detail clear picture of the physical basis of this effect, but I
>>know that the exposed stones are not radioactive (i.e., not activated)
>>and this effect could be reversed by heating the stones to restore its
>>original colors. On the other hand, I have heard that there are
>>different irradiation techniques, which are followed in different places
>>in the world, help increasing the prices of the gemstones by changing
>>their features (inducing different colors, glowing ...etc.) at the same
>>time they may induce radiation risk in these stones (!?). Does any body
>>have information about:
>>
>>1. The physical basis of gemstone coloring by gamma rays or electron
>>beams.
>>2. Any irradiation techniques, other than the one mentioned in the first
>>point, are used in gemstone industry.
>>3. Are there any regulations govern these techniques?
>>
>>Answers and comments would be appreciated ...
>>
>>Best regards.
>>--
>>Khalid Aleissa, Ph.D.
>>224B, Institute of Atomic Energy Research
>>King Abdulaziz City for Science and Technology
>>P. O. Box 6086
>>Riyadh 11442
>>Saudi Arabia
>>Tel (+9661) 481-3617
>>Fax. (+9661) 481-3887
>>e-mail: kaleissa@kacst.edu.sa
>>
>>
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>
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