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Occurrence

Niobium is estimated to be the 33rd most abundant element in the Earth's crust, at 20 ppm. Some believe that the abundance on Earth is much greater, and that the element's high density has concentrated it in Earth's core. The free element is not found in nature, but niobium occurs in combination with other elements in minerals. Minerals that contain niobium often also contain tantalum. Examples include columbite ((Fe,Mn)Nb O) and columbite–tantalite (or coltan, (Fe,Mn)(Ta,Nb) O). Columbite–tantalite minerals (the most common species being columbite-(Fe) and tantalite-(Fe), where "-(Fe)" is the Levinson suffix indicating the prevalence of iron over other elements such as manganese) that are most usually found as accessory minerals in pegmatite intrusions, and in alkaline intrusive rocks. Less common are the niobates of calcium, uranium, thorium and the rare earth elements. Examples of such niobates are pyrochlore ((Na,Ca) Nb O (OH,F)) (now a group name, with a relatively common example being, e.g., fluorcalciopyrochlore) and euxenite (correctly named euxenite-(Y)) ((Y,Ca,Ce,U,Th)(Nb,Ta,Ti) O). These large deposits of niobium have been found associated with carbonatites (carbonate - silicate igneous rocks) and as a constituent of pyrochlore.

The three largest currently mined deposits of pyrochlore, two in Brazil and one in Canada, were found in the 1950s, and are still the major producers of niobium mineral concentrates. The largest deposit is hosted within a carbonatite intrusion in Araxá, state of Minas Gerais, Brazil, owned by CBMM (Companhia Brasileira de Metalurgia e Mineração); the other active Brazilian deposit is located near Catalão, state of Goiás, and owned by China Molybdenum, also hosted within a carbonatite intrusion. Together, those two mines produce about 88% of the world's supply. Brazil also has a large but still unexploited deposit near São Gabriel da Cachoeira, state of Amazonas, as well as a few smaller deposits, notably in the state of Roraima.

The third largest producer of niobium is the carbonatite-hosted Niobec mine, in Saint-Honoré, near Chicoutimi, Quebec, Canada, owned by Magris Resources. It produces between 7% and 10% of the world's supply.