Peterandresenite Explained

Peterandresenite
Category:	Oxide, Hexaniobate
Formula:	Mn4Nb6O19•14H2O
Imasymbol:	Pan^[1]
System:	Monoclinic
Class:	Prismatic (2/m) (same H-M symbol)
Symmetry:	C2/m
Unit Cell:	a = 15.33, b = 9.41, c = 11.28 [Å], β = 118.65° (approximated); Z = 2
Color:	Orange
Habit:	crystals (equidimensional)
Cleavage:	None
Fracture:	Uneven
Tenacity:	Brittle
Mohs:	2-2.5
Luster:	Vitreous or resinous
Streak:	Pale orange
Density:	3.05 (calc.), 3.10 (meas.) [g/cm<sup>3</sup>]
Diaphaneity:	Transparent or translucent
References:	^[2]

Peterandresenite is a very rare mineral,^[3] the first known natural hexaniobate. Its chemical formula is Mn₄Nb₆O₁₉•14H₂O. Its structure contains a special type of octahedron: Lindqvist ion. Peterandresenite was found in a pegmatite of the Larvik complex in Norway.^[4] It is somewhat similar to other unique niobium minerals, aspedamite and menezesite.^{[5] [6]}

Occurrence

Peterandresenite was discovered in AS Granit quarry, Tvedalen, Larvik, Vestfold, Norway.

Notes and References

1. Warr. L.N.. 2021. IMA–CNMNC approved mineral symbols. Mineralogical Magazine. 85. 3 . 291–320. 10.1180/mgm.2021.43 . 2021MinM...85..291W . 235729616 . free.
2. https://www.mineralienatlas.de/lexikon/index.php/MineralData?mineral=Peterandresenite Mineralienatlas
3. Web site: Peterandresenite: Peterandresenite mineral information and data . Mindat.org . 2016-03-04.
4. Friis, H., Larsen, A.O., Kampf, A.R., Evans, R.J., Selbekk, R.S., and Sánchez, A.A., 2014. Peterandresenite, Mn₄Nb₆O₁₉·14H₂O, a new mineral containing the Lindqvist ion from a syenite pegmatite of the Larvik Plutonic Complex, southern Norway. European Journal of Mineralogy 26, 567-576
5. Web site: Aspedamite: Aspedamite mineral information and data . Mindat.org . 2016-03-08.
6. Web site: Menezesite: Menezesite mineral information and data . Mindat.org . 2016-03-08.