Radium is a ignoble metal, which chemically is very similar to barium. Radium metal is radioactive, the most stable isotope, 226Ra, has a half-life of 1602 years and decays to radon. Radium metal was discovered by Marie Curie and played an important role in the earliest research of radioactivity. Up to the late 1920s, Radium was treated quite unscrupulously and was even promoted as being healthy. A popular application was for self-luminous paint in clock dials until the 1960s. Today radium is hardly used for anything, except in very small amounts for research. Natural radium is produced in the decay chain of uranium from thorium.

Radium clock hands can be collected in safe way sealed in ampoule and permanently casted in resina.