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April 20 2012 6 20 /04 /April /2012 13:16

Promethium, being an extremely radioactive and unstable element, is impossible to obtain in pure form. However, some old glow-in-the-dark watches that are radioactive have used promethium as the radioactive element. This is after the radium watches were discontinued and before tritium came into more common use.

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Published by LanthanumK - in Elements
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Eslam Maher 04/21/2012 00:13


Very interesting. What about today's watches which has the arrows glowing?

LanthanumK 04/21/2012 02:13



If it fades after extended exposure to the dark, it is probably copper-doped or silver-doped zinc sulfide.


If it lasts for an extended period of time in the dark, it is probably tiny tubes of tritium gas with a phosphor to catch the radiation and convert it to light.