Crossword clues for columbite
The Collaborative International Dictionary
Columbite \Co*lum"bite\, n. [Cf. F. colombite. See Columbium.] (Min.) A mineral of a black color, submetallic luster, and high specific specific gravity. It is a niobate (or columbate) of iron and manganese, containing tantalate of iron; -- first found in New England.
Wiktionary
n. (context mineral English) A black mineral that is a mixed iron and manganese niobate and tantalate, and is the main ore of niobium and tantalum.
WordNet
n. a black mineral that is an ore of niobium and tantalum [syn: niobite]
Wikipedia
Columbite, also called niobite, niobite-tantalite and columbate [( Fe, Mn) Nb O], is a black mineral group that is an ore of niobium. It has a submetallic luster and a high density and is a niobate of iron and manganese. This mineral group was first found in Haddam, Connecticut, in the United States. It forms a series with the tantalum-dominant analogue ferrotantalite and one with the manganese-dominant analogue manganocolumbite. The iron-rich member of the columbite group is ferrocolumbite. Some tin and tungsten may be present in the mineral. Yttrocolumbite is the yttrium-rich columbite with the formula (Y,U,Fe)(Nb,Ta)O. It is a radioactive mineral found in Mozambique.
Columbite has the same composition and crystal symmetry ( orthorhombic) as tantalite. In fact, the two are often grouped together as a semi-singular mineral series called columbite-tantalite or coltan in many mineral guides. However, tantalite has a much greater specific gravity than columbite, more than 8.0 compared to columbite's 5.2.
Columbite is also very similar to tapiolite. Those minerals have same chemical composition but different crystal symmetry: orthorhombic for columbite and tetragonal for tapiolite. The largest documented single crystal of columbite consisted of plates thick measuring .
Usage examples of "columbite".
He must have got hold of about £10,000 from somewhere because the Express says that in 1946 he’d bought three tons of Columbite, which cost him around £3000 a ton.
Also made of Columbite alloy or they’d break away with the colossal air pressure.
He must have got hold of about £10,000 from somewhere because the Express says that in 1946 he'd bought three tons of Columbite, which cost him around £3000 a ton.
Also made of Columbite alloy or they'd break away with the colossal air pressure.
Drax's voice of controlled anger broke in on Bond's thoughts as he stood fingering the sharp leading edge of the tail of one of the Columbite fins.