Ferrocolumbite
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Ferrocolumbite, also called niobite, columbate and columbite [(Fe, Mn)(Nb, Ta)2O6] is a black mineral that is an ore of niobium and tantalum. It has a submetallic luster and a high specific gravity and is a niobate of iron and manganese, containing tantalate of iron. This mineral was first found at Haddam, Middlesex County, Connecticut in New England, USA. It forms a series with the tantalum-dominant analogue Ferrotantalite and one with the manganese-dominant analogue Manganocolumbite.
In 1925, German chemists Walter Noddack, Otto Berg and Ida Tacke reported the discovery of element 43 and named it masurium. The group bombarded columbite with a beam of electrons and deduced element 43 was present by detecting faint x-rays. Their method was not confirmed until 1999 when American David Curtis of the Los Alamos National Laboratory successfully repeated the experiment.Template:Inote