Samarium

Samarium is a silvery rare-earth metal, found in the same minerals as neodymium and cerium. Paul-Émile Lecoq de Boisbaudran identified it in 1879 in a mineral called samarskite, itself named after a Russian mining official, Vasili Samarsky-Bykhovets. That makes samarium the first element named, indirectly, after a person.

In the 1960s and 1970s, samarium mixed with cobalt made the strongest magnets known. They have since been overtaken by the neodymium magnet, but samarium-cobalt magnets still win where things get hot or corrosive, such as in aircraft, missiles and high-performance motors. A radioactive form, samarium-153, is used to ease pain from cancer that has spread to the bones.