Radioactive Gemstones

[Khalid Aleissa <kaleissa@kacst.edu.sa>]

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


************************************************************************
The RADSAFE Frequently Asked Questions list, archives and subscription
information can be accessed at http://www.ehs.uiuc.edu/~rad/radsafe.html