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Samarium is not absorbed by plants to a measurable concentration and so is normally not part of human diet. However, a few plants and vegetables may contain up to 1 part per million of samarium. Insoluble salts of samarium are non-toxic and the soluble ones are only slightly toxic.
Some of the bastnäsites contain OH − instead of F − and receive the name of hydroxylbastnasite. Most bastnäsite is bastnäsite-(Ce), and cerium is by far the most common of the rare earths in this class of minerals. Bastnäsite and the phosphate mineral monazite are the two largest sources of cerium and other rare-earth elements.
Cerium is the most abundant of all the lanthanides and the 25th most abundant element, making up 68 ppm of the Earth's crust. [45] This value is the same of copper, and cerium is even more abundant than common metals such as lead (13 ppm) and tin (2.1 ppm).
The USGS study team has located a sizable area of rocks in the center of an extinct volcano containing light rare-earth elements including cerium and neodymium. It has mapped 1.3 million metric tons of desirable rock, or about ten years of supply at current demand levels. The Pentagon has estimated its value at about $7.4 billion. [185]
The rare earth element neodymium is found in monazite, making it a rare mineral. [25] Moreover, monazite contains many other rare metals such as cerium, lanthanum, praseodymium, and samarium, making it a critical source of renewable energy. [26] Recycled magnets can also be derived from these minerals due to the metals they contain. [25]
The four elements associated with non-scientists were not named in their honor but named for something else bearing their name: samarium for the mineral samarskite from which it was isolated; and americium, berkelium and livermorium after places named for them.
The Earth's crust is one "reservoir" for measurements of abundance. A reservoir is any large body to be studied as unit, like the ocean, atmosphere, mantle or crust. Different reservoirs may have different relative amounts of each element due to different chemical or mechanical processes involved in the creation of the reservoir. [1]: 18
The principal commercially viable ore of lutetium is the rare-earth phosphate mineral monazite, (Ce,La,etc.)PO 4, which contains 0.003% of the element. The main mining areas are China , United States , Brazil , India , Sri Lanka and Australia .