Betafite is a mineral in the pyrochlore

Pyrochlore

Pyrochlore 2Nb2O6 is a solid solution between the niobium end member , and the tantalum end member .-Occurrence:...

 group, with the chemical formula (Ca,U)₂(Ti,Nb,Ta)₂O₆(OH). Betafite typically occurs as a primary mineral in granite

Granite

Granite is a common and widely occurring type of intrusive, felsic, igneous rock. Granite usually has a medium- to coarse-grained texture. Occasionally some individual crystals are larger than the groundmass, in which case the texture is known as porphyritic. A granitic rock with a porphyritic...

 pegmatites, rarely in carbonatite

Carbonatite

Carbonatites are intrusive or extrusive igneous rocks defined by mineralogic composition consisting of greater than 50 percent carbonate minerals. Carbonatites may be confused with marble, and may require geochemical verification....

s. Betafite was discovered in 1912 at Betafo, Malagasy Republic.

Betafite crystallizes as Isometric - Hexoctahedral

Cubic crystal system

In crystallography, the cubic crystal system is a crystal system where the unit cell is in the shape of a cube. This is one of the most common and simplest shapes found in crystals and minerals....

 crystals and occurs typically as anhedral grains with color varying from red, greenish brown, dark brown to black. Its luster is vitreous to greasy. Betafite is a radioactive mineral.