Promethium metal is the second element after technetium metal, of which no stable isotopes exist. However, Promethium metal is much more unstable than this, the most long-lived isotope, 145Pm, has a half-life of just under 18 years. The only natural isotope, 147Pm, has a half-life of only about two and a half years. This on Earth occurs only in traces, most of it is from nuclear waste. There are some few, very special applications for promethium, e.g. in radioisotope thermoelectric generators. Very few stars contain promethium, which they seem to produce themselves, however they may do that. Promethium paint was used in subaqueous watches and also in big alarm clock hands.
Incredible rare representative sample of Promethium as big watch hand of the 50's
Dimensions: about 3cm long, it glows in the dark. This is a MUST HAVE for every element collectors.
Promethium watch hand, old Promethium paint for collection, casted in acrylic inside a labeled glass vial.