Betafite
>
Betafite is a mineral group in the pyrochlore supergroup, with the chemical formula (Ca, U)₂(Ti, Nb, Ta)₂O₆. Betafite typically occurs as a primary mineral in granite pegmatites, rarely in carbonatites. Wikipedia
Color: Brown, Black, Brownish green, Yellow, Greenish black
Crystal habit: Massive - Granular
Crystal system: Cubic
Mohs scale hardness: 5 - 5.5