Rare-earth element
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The rare-earth elements, also called rare-earth metals, or rare earths, are a set of 17 nearly indistinguishable lustrous silvery-white soft heavy metals. The 15 lanthanides, along with scandium, and
Rare-earth ore (shown with a 19 mm diameter US 1 cent coin for size comparison)
Refined rare-earth oxides are heavy, gritty powders usually brown or black, but can be lighter colors as shown here. Back row: gadolinium · praseodymium · cerium Middle row: samarium · lanthanum Front: neodymium
A false-color satellite image of the Bayan Obo Mining District, 2006
Terbium
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Terbium is a chemical element; it has symbol Tb and atomic number 65. It is a silvery-white, rare earth metal that is malleable and ductile. The ninth member of the lanthanide series, terbium is a fai
Terbium sulfate, Tb2(SO4)3 (top), fluoresces green under ultraviolet light (bottom)
Carl Gustaf Mosander, the scientist who discovered terbium, lanthanum and erbium
Xenotime, a mineral source of rare earth elements including terbium