Niobium minerals

thumb|upright|right|A piece of columbite–tantalite, size 6.0 × 2.5 × 2.1 cm Coltan (short for columbite–tantalite and known industrially as tantalite) is a dull black metallic ore from which the elements niobium and tantalum are extracted. The niobium-dominant mineral in coltan is columbite (after niobium's original name columbium), and the tantalum-dominant mineral is tantalite.

Columbite, also called niobite, niobite-tantalite and columbate, with a general chemical formula of , is a black mineral group that is an ore of niobium. It has a submetallic luster, a high density, and is a niobate of iron and manganese. Niobite has many applications in aerospace, construction and the medical industry. Dating columbite minerals is primarily completed by uranium–lead dating, a slow process.

Euxenite, or euxenite-(Y) (the official mineralogical name), is a brownish black mineral with a metallic luster.

Pyrochlore () is a mineral group of the niobium end member of the pyrochlore supergroup. Pyrochlore is also a term for the crystal structure Fdm. The name is from the Greek , fire, and , green because it typically turns green on ignition in classic blowpipe analysis.

Samarskite is a radioactive rare earth mineral series which includes samarskite-(Y), with the chemical formula and samarskite-(Yb), with the chemical formula . The formula for samarskite-(Y) is also given as .

thumb|Betafite, Gunnison, Colorado

Fergusonite is a mineral comprising a complex oxide of various rare-earth elements. The general chemical formula of fergusonite is (Y,REE)NbO4, where REE = rare-earth elements in solid solution with Y. Yttrium is usually dominant (the mineral in this case being referred to as fergusonite-(Y)), but sometimes Ce or Nd may be the major rare-earth component (in fergusonite-(Ce) and fergusonite-(Nd), respectively). The other rare-earth elements are present in smaller amounts, and tantalum sometimes substitutes for some of the niobium. There are fergusonite-beta-(Nd), fergusonite-beta-(Y), fergusoni

Aeschynite-(Y) (or Aeschinite-(Y), Aeschynite-(Yt), Blomstrandine, Priorite) is a rare earth mineral of yttrium, calcium, iron, thorium, titanium, niobium, oxygen, and hydrogen with the chemical formula . Its name comes from the Greek word for "shame". Its Mohs scale rating is 5 to 6.

Polycrase or polycrase-(Y) is a black or brown metallic complex uranium yttrium oxide mineral with the chemical formula . It is amorphous. It has a Mohs hardness of 5 to 6 and a specific gravity of 5. It is radioactive due to its uranium content (around 6%). It occurs in granitic pegmatites.

Nenadkevichite is a rare silicate mineral containing niobium with the chemical formula . It forms brown to yellow to rose colored orthorhombic dipyramidal crystals with a dull to earthy luster. It has a Mohs hardness of 5 and a specific gravity of 2.86.

Zirkelite is an oxide mineral with the chemical formula . It occurs as well-formed fine sized isometric crystals. It is a black, brown or yellow mineral with a hardness of 5.5 and a specific gravity of 4.7.

Simpsonite has a general formula of . It occurs as euhedral to subhedral tabular to short and prismatic crystals, commonly in subparallel groups. Under the petrographic microscope it has a very high relief.

Tapiolite [(Fe, Mn)(Nb, Ta)2O6] is a black mineral series that is an ore of niobium and tantalum. The tapiolite group includes tapiolite-(Fe) or ferrotapiolite and tapiolite-(Mn) or manganotapiolite. Tapiolite-(Fe) is by far the more common of the two.

Zimbabweite is a yellow brown mineral with orthorhombic crystal habit and a hardness of 5, with formula . It is generally classed as an arsenite but is notable for also containing niobium and tantalum. It was discovered in 1986 in kaolinized pegmatite, i.e. weathered to clay, in Zimbabwe.

Rynersonite is an oxide mineral. It crystallizes in the orthorhombic crystal system. It is dull, translucent mineral, fibrous in nature. Usually off-white to pale pink in color. It occurs in granitic pegmatites and was first described for an occurrence in San Diego County, California in 1978.

Raslakite is a rare mineral of the eudialyte group with the chemical formula . This formula is based on the original one, and is extended to show the presence of cyclic silicate groups. The additional silicon and oxygen shown in separation from the cyclic groups (in parentheses) are in fact connected with two 9-fold rings. The mineral has lowered symmetry (space group R3, instead of more specific for the group R3m one), similarly to some other eudialyte-group members: aqualite, labyrinthite, oneillite and voronkovite. The specific feature of raslakite is, among others, the presence of sodium a

Vigezzite is a variant of the mineral aeschynite containing calcium, cerium, niobium, tantalum, and titanium. It was first discovered near Orcesco, Valle Vigezzo, Provo Novara, Northern Italy, in cavities of an albitic rock. The crystals of Vigezzite are flat prismatic crystals up to 2-3 mm length of an orange-yellow color.The name Vigezzite was chosen to draw attention to the locality that has produced the first occurrence of a Ca-Nb-Ta-mineral with Nb dominance over Ta, crystallizing with the aeschynite structure. The ideal chemical formula for vigezzite is (Ca,Ce),(Nb,Ta,Ti)2O6

Zirsilite-(Ce) is a very rare mineral of the eudialyte group, with formula . The original formula was extended to show the presence of cyclic silicate groups and the presence of silicon at the M4 site, according to the nomenclature of the eudialyte group. Zirsilite-(Ce) differs from carbokentbrooksite in cerium-dominance over sodium only. Both minerals are intimately associated. The only other currently known representative of the eudialyte group having rare earth elements (in particular cerium, as suggested by the "-Ce)" Levinson suffix in the name) in dominance is johnsenite-(Ce).

thumb|Oxyyttropyrochlore-(Y) (obruchevite) Oxyyttropyrochlore-(Y), also referred to as "obruchevite" or "yttropyrochlore-(Y)", is a potential (not yet accepted) zero-valent-dominant mineral of the pyrochlore group. Its formula can be written as (Y,◻)2Nb2O2O.

Billwiseite is a very rare oxide mineral found at the pegmatite commonly referred to as "Stak Nala" located within a few hundred yards from the village of Toghla in the Stak Nala, Gilgit-Baltistan, Pakistan. It has only been found as a coating on a single crystal of lepidolite. The sole rock containing Billwiseite is kept at the Royal Ontario Museum, catalogue number M5595.

Zircophyllite is a complex mineral, formula . It crystallizes in the triclinic – pinacoidal crystal class as dark brown to black micaceous plates. It has perfect 001 cleavage, a Mohs hardness of 4 to 4.5 and a specific gravity of 3.34. Its indices of refraction are nα=1.708 nβ=1.738 nγ=1.747 and it has a 2V optical angle of 62°.

Ferrokentbrooksite is a moderately rare mineral of the eudialyte group, with formula . The original formula was extended form to show the presence of cyclic silicate groups and presence of silicon at the M4 site, according to the nomenclature of eudialyte group. As suggested by its name, it is the (ferrous) iron analogue of kentbrooksite. When compared to the latter, it is also chlorine-dominant instead of being fluorine-dominant. The original (holotype) material is also relatively enriched in rare earth elements, including cerium and yttrium.

Achalaite ((Fe2+, Mn)(Ti, Fe3+, Ta)(Nb, Ta)2O8) is a black mineral of the wodginite group, first discovered in 2013.

Georgbarsanovite is a very rare mineral of the eudialyte group, formerly known under unaccepted name as barsanovite, with formula . The original formula was extended to show the presence of cyclic silicate groups and the domination of silicon at the M4 site. "REE", standing for rare earth elements, is dominated by cerium. Georgbarsanovite is characterized in dominance of manganese at the N4 site. It also differs from most other accepted group representatives in its colour. The mineral was found in nepheline pegmatite near Petrelius River, Khibiny massif, Kola Peninsula, Russia. It is named aft

Alsakharovite-Zn (IMA symbol: Ask-Zn) is an extremely rare alkaline strontium zinc titanium silicate mineral from the cyclosilicates class, with the chemical formula , from alkaline pegmatites. It belongs to the labuntsovite group.

Feklichevite is a rare mineral of the eudialyte group with the formula Na11Ca9(Fe3+,Fe2+)2Zr3NbSi(Si3O9)2(Si9O27)2. The original formula was extended to show the presence of cyclic silicate groups and presence of silicon at the M4 site, according to the nomenclature of eudialyte group. When compared to other minerals of the group, feklichevite characterizes in the presence of ferric iron (thus similar to ikranite, mogovidite and fengchengite) and dominance of calcium at the N4 site. Calcium is ordered in the structure and is also present at the M1 site. Other iron-bearing minerals of the group

Peterandresenite is a very rare mineral, the first known natural hexaniobate. Its chemical formula is Mn4Nb6O19•14H2O. Its structure contains a special type of octahedron: Lindqvist ion. Peterandresenite was found in a pegmatite of the Larvik complex in Norway. It is somewhat similar to other unique niobium minerals, aspedamite and menezesite.

Schiavinatoite is a very rare borate mineral, and the niobium endmember of a solid solution formed with béhierite.

Kentbrooksite is a moderately rare mineral of the eudialyte group, with chemical formula . This extended formula shows the presence of cyclic silicate groups and dominance of Si at the M4 site, according to the nomenclature of the eudialyte group. The characteristic features of kentbrooksite, that make it different from eudialyte are: (1) dominancy of fluorine (the only currently known example among the whole group), (2) dominancy of manganese, and (3) dominancy of niobium. Trace hafnium and magnesium are also reported. Kentbrooksite is relatively common when compared to most other species of

Nioboholtite is an extremely rare mineral with the formula (Nb0.6[]0.4)Al6BSi3O18. It is the niobium-rich member of the dumortierite supergroup, and the niobium analogue of holtite of the holtite group. It is one of three quite recently found minerals of this group, the other two being titanoholtite and szklaryite, all coming from the Szklary village near Ząbkowice Śląskie in Poland. They occur in a unique pegmatite. Nioboholtite and schiavinatoite are both minerals with essential niobium and boron.