columbite

[kuh-luhm-bahyt]
noun
a black, crystalline mineral, iron niobate, (Fe, Mn)Nb 2 O 6 , the principal ore of niobium, an end member of a series of solid solutions in which manganese and tantalum combine to form tantalite.

Origin:
1795–1805; columb(ium) + -ite1

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columbite (kəˈlʌmbaɪt)
 
n
Also called: niobite a black mineral consisting of a niobium oxide of iron and manganese in orthorhombic crystalline form: occurs in coarse granite, often with tantalite, and is an ore of niobium. Formula: (Fe, Mn)(Nb)2O6
 
[C19: from columbium + -ite1]

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columbite

hard, black (often iridescent), heavy oxide mineral of iron, manganese, and niobium [(Fe,Mn)Nb2O6]. Tantalum atoms replace niobium atoms in the crystal structure to form the mineral tantalite, which is similar but much more dense. These minerals are the most abundant and widespread of the naturally occurring niobates and tantalates and are important ores, their elements niobium and tantalum serving as constituents of corrosion-resistant metal alloys. Columbite and tantalite are found together in granite, pegmatites, and placer deposits. They occur abundantly in western Australia, Madagascar, and South Dakota, U.S. The element niobium (formerly called columbium) was first recognized in columbite and originally was named after the mineral. For detailed physical properties, see oxide mineral (table)

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Encyclopedia Britannica, 2008. Encyclopedia Britannica Online.
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Example sentences
Tantalum occurs principally in the mineral columbite-tantalite.
There were no published price quotes for columbium-bearing columbite and pyrochlore concentrates.
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