 Samarium is not found free in nature , but , like other rare earth elements , is contained in many minerals , including monazite , bastnäsite , cerite , gadolinite and samarskite ; monazite ( in which samarium occurs at concentrations of up to 2 @.@ 8 % ) and bastnäsite are mostly used as commercial sources . World resources of samarium are estimated at two million tonnes ; they are mostly located in China , US , Brazil , India , Sri Lanka and Australia , and the annual production is about 700 tonnes . Country production reports are usually given for all rare @-@ earth metals combined . By far , China has the largest production with 120 @,@ 000 tonnes mined per year ; it is followed by the US ( about 5 @,@ 000 tonnes ) and India ( 2 @,@ 700 tonnes ) . Samarium is usually sold as oxide , which at the price of about 30 USD / kg is one of the cheapest lanthanide oxides . Whereas mischmetal – a mixture of rare earth metals containing about 1 % of samarium – has long been used , relatively pure samarium has been isolated only recently , through ion exchange processes , solvent extraction techniques , and electrochemical deposition . The metal is often prepared by electrolysis of a molten mixture of samarium ( III ) chloride with sodium chloride or calcium chloride . Samarium can also be obtained by reducing its oxide with lanthanum . The product is then distilled to separate samarium ( boiling point 1794 ° C ) and lanthanum ( <unk> <unk> ° C ) . 
