Occurrence
| Occurrence and Production of Promethium |
| Occurrence
|
| Promethium can be formed as a product of uranium fission. 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. |
| Promethium has also been identified in the spectrum of the star HR 465 in Andromeda, and possibly HD 101065 (Przybylski's star) and HD 965. |