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Thus, despite its position as one of the so-called rare-earth metals, cerium is actually not rare at all. [46] Cerium content in the soil varies between 2 and 150 ppm, with an average of 50 ppm; seawater contains 1.5 parts per trillion of cerium. [38] Cerium occurs in various minerals, but the most important commercial sources are the minerals ...
One square patch of metal-rich mud 2.3 kilometers wide might contain enough rare earths to meet most of the global demand for a year, Japanese geologists report in Nature Geoscience." "I believe that rare[-]earth resources undersea are much more promising than on-land resources," said Kato.
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.
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 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
This super rare penny sold for six figures because it’s only one of two dates that feature zinc-coated steel. It’s worth mentioning that the 1944 version is more rare than the 1943 one.
Samarium-149 is the second most important neutron poison in nuclear reactor physics. Samarium-151, produced at lower yields, is the third most abundant medium-lived fission product but emits only weak beta radiation. Both have high neutron absorption cross sections, so that much of them produced in a reactor are later destroyed there by neutron ...