Peterandresenite is a very rare mineral, the first known natural hexaniobate. Its chemical formula is Mn<sub>4</sub>Nb<sub>6</sub>O<sub>19</sub>â¢14H<sub>2</sub>O. 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.
Peterandresenite was discovered in AS Granit quarry, Tvedalen, Larvik, Vestfold, Norway.