Class : Sulfides and sulfosalts
    Subclass : Sulfides
    Crystal system : Cubic
    Chemistry : NiSbS
    Rarity : Uncommon

Ullmannite is a mineral of certain high-temperature hydrothermal veins of nickel and cobalt or copper, in which it is associated with other nickel minerals, mainly gersdorffite and nickeline, chalcopyrite or pyrrhotite. It forms a continuous series with willyamite, the cobalt pole of the series. It was named in honor of the German chemist and mineralogist Johann Christoph Ullmann who discovered the mineral. Crystallized ullmannite is most often cubic, with striated faces, more rarely octahedral, of steel gray to silvery white color. As and Bi contents are not rare. It is an ancillary ore of nickel.

Main photo : Ullmannite from Roc Blanc, Morocco © Joan Rosell

Twinning is known on [110].

No fakes listed for this mineral species.