Dark red microcrystals of the Mn -V oxide ansermetite from the TL in Switzerland (Fianel, Ausserferrera, Ferrera Valley, Hinterrhein, Grisons, Switzerland). Ex. Erich Laskowski collection (USA). — Photo: David Hospital · CC BY 4.0
Ansermetite
Ansermetite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Mn²⁺V⁵⁺₂O₆·4H₂O.
It crystallizes in the monoclinic crystal system (space group C2/c).
Key properties: specific gravity 2.57; Orange streak; Adamantine luster.
IMA symbol Anm, IMA status: approved, named in 2002.
Of synsedimentary to diagenetic origin, in thin fractures, in a metamorphosed exhalative Fe-Mn deposit in carbonate rocks.
It is found associated with Fianelite, Fe oxyhydroxides, silica (Fianel mine); kegginite, gypsum, mesaite, sherwoodite (Packrat mine).
The mineral was named to honor Stefan Ansermet (b. 1964), Swiss mineralogist for contributions to the descriptive mineralogy and photography of Alpine mineralogical wealth.