Short answers, pulled from the story.
Samarium was named after Colonel Vassili Samarsky-Bykhovets, the Chief of Staff of the Russian Corps of Mining Engineers. He granted access to German mineralogists Gustav and Heinrich Rose to study samples from the Ural Mountains in the 1840s. This indirect honor made him the first person to have a chemical element named after him.
French chemist Paul-Émile Lecoq de Boisbaudran isolated samarium from samarskite in 1879. The pure samarium(III) oxide was produced in 1901 by Eugène-Anatole Demarçay, and the metallic form was isolated by Wilhelm Muthmann in 1903. The symbol Sm was adopted in the 1920s, replacing the alternative Sa.
Samarium is a moderately hard, silvery metal with a boiling point of 1,794 degrees Celsius and an atomic radius of 238 picometers. It exhibits multiple crystal structures including rhombohedral at room temperature, hexagonal close-packed at 733 degrees Celsius, and body-centered cubic at 922 degrees Celsius. Under extreme pressure of 40 kilobars, it adopts a double-hexagonally close-packed structure.
Samarium-149 is a potent neutron absorber with a cross section of 41,000 barns for thermal neutrons that builds up to an equilibrium concentration over about 500 hours. It is used in control rods for nuclear reactors and is a decay product of neodymium-149. The isotope is not radioactive and does not vanish through decay, creating a neutron poison effect that must be managed.
Samarium-153 is a beta emitter with a half-life of 46.285 hours used to treat metastatic bone cancer in lung, prostate, breast, and osteosarcoma cases. It is chelated with ethylene diamine tetramethylene phosphonate to form the drug samarium-153 lexidronam, known by the trade name Quadramet. The drug is injected intravenously and targets cancer cells in bones where 45% of the samarium is deposited.
The samarium-neodymium dating method relies on the analysis of relative concentrations of samarium-147 and neodymium-143 isotopes. Samarium-147 is an extremely long-lived radioisotope with a half-life of 1.066 billion years that undergoes alpha decay to neodymium-143. This process determines the age and origin of rocks and meteorites and is useful because both elements are lanthanides with similar physical and chemical properties.