Irradiated Pestle
![Irradiated Pestle](../../../img/museum/lichtenberg/glass/pestle.jpg)
The pestle of this glass mortar and pestle set turned a beautiful purple as a result of an exposure to cobalt-60 (Co-60) gamma rays. The dose was not determined but it was probably on the order of one megarad.
Unfortunately I do not know the identity of the impurity in the glass that is responsible for the purple color.