What is "peterandresenite"

Peterandresenite is a very rare mineral, the first known natural hexaniobate. Its chemical formula is MnNbO•14HO. 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.