Samarium, suh MAR ee uhm (chemical symbol, Sm), is a chemical element and one of the rare-earth metals. Alloys of samarium and cobalt are excellent magnetic materials and have many commercial uses. Samarium has a silver color and slowly oxidizes in air. The common oxide has a pale yellow color and is rapidly soluble in most acids. Paul Emile Lecoq de Boisbaudran of France discovered samarium in 1879. The element is named after the Russian engineer Colonel V. E. Samarski.