Category Silicate mineral Crystal system Orthorhombic | Formula
(repeating unit) (Nb0.6[]0.4)Al6BSi3O18 Space group Pnma | |
Crystal class Dipyramidal (mmm)
H-M symbol: (2/m 2/m 2/m) Unit cell a = 47.00, b = 11.83
c = 20.24 [Å] (approximated) | ||
Nioboholtite is an extremely rare mineral with the formula (Nb0.6[]0.4)Al6BSi3O18. It is niobium-rich member of dumortierite supergroup, and 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.
Association
Nioboholtite is mainly associated with holtite and a number of other minerals (see szklaryite).
References
Nioboholtite Wikipedia(Text) CC BY-SA