 A few large deposits produce or produced a significant amount of the world production . The Bayan Obo iron ore deposit contains significant amounts of bastnäsite and monazite and is , with an estimated 36 million tonnes of rare earth element oxides , the largest known deposit . The mining operations at the Bayan Obo deposit made China the largest supplier of rare earth elements in the 1990s . Only 0 @.@ 2 % of the rare earth element content is europium . The second large source for rare earth elements between 1965 and its closure in the late 1990s was the Mountain Pass rare earth mine . The bastnäsite mined there is especially rich in the light rare earth elements ( La @-@ <unk> , <unk> , and Y ) and contains only 0 @.@ 1 % of europium . Another large source for rare earth elements is the loparite found on the <unk> peninsula . It contains besides niobium , tantalum and <unk> up to 30 % rare earth elements and is the largest source for these elements in Russia . 
