Peterandresenite Field of view: 0.3 mm Locality: A/S Granit Quarry (TL), Tuften, Tvedalen, Larvik, Vestfold, Norway ( locality at mindat.org ) — Photo: Henk Smeets – tomeikminerals.com · CC BY 4.0
Peterandresenite
The first natural hexaniobate — a manganese niobate whose structure hosts the Lindqvist octahedron.
Intro adapted from Wikipedia (CC BY-SA).
Peterandresenite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Mn₄Nb₆O₁₉·14H₂O.
It crystallizes in the monoclinic crystal system (space group C2/m). It is a member of the Peterandresenite structural group.
Key properties: Mohs hardness 2–2.5; specific gravity 3.1; Pale orange streak; Vitreous to resinous luster; optically biaxial.
IMA symbol Pan, IMA status: approved, named in 2012.
Formed at the hydrothermal stage on fracture surfaces and in tiny vugs in the center of a miaskitic pegmatite dike within the larvikites of a plutonic complex.
It is found associated with Analcime, fluorapophyllite-(K), arsenopyrite, behoite, bertrandite, calcite, chiavennite, chlorite, epididymite, Mn2+-rich fayalite, fluorite, galena.
The mineral was named to honor Peter Andresen (b. 1971), the mineral collector who first found the mineral.