Promethium (Pm)
Promethium (Pm) is contained in the following mineral:
Area of application: It is the only naturally radioactive rare earth element, and virtually all promethium in the earth’s crust has long ago decayed into other elements. Today, it is largely artificially created, and used in watches, pacemakers, and in scientific research.
Only trace amounts can be found in naturally occurring ores: a sample of pitchblende has been found to contain promethium at a concentration of four parts per quintillion (1018) by mass. Uranium is thus "responsible" for 560 g of promethium in Earth's crust.
Promethium has also been identified in the spectrum of the star HR 465 in Andromeda; it also has been found in HD 101065 (Przybylski's star) and HD 965. Because of the short half-life of promethium isotopes, they should be formed near the surface of those stars.
References
https://en.wikipedia.org
https://en.wikipedia.org/wiki/Promethium
https://rcs6periodictable.wikispaces.com/Pm+-+Promethium
http://www.periodictablepen.com/1-chemical-elements/promethium/pictures.html