:Yellow to orange platy crystals of rüdlingerite (0.1 mm long) with dark orange to red fianelite crystals from Valletta. The image belongs to the article "Rüdlingerite, Mn2+2V5+As5+O7·2H2O, a New Species Isostructural with Fianelite" ( https://www.mdpi.com/2075-163X/10/11/960/htm ) published with a CC license. — Photo: Roberto Bracco · CC BY 4.0
Fianelite
A manganese vanadate from iron-manganese ores, named for the Fianel mine in Switzerland's Val Ferrera.
Intro adapted from Wikipedia (CC BY-SA).
Fianelite is an IMA-recognized mineral species in the vanadate class, with the chemical formula Mn²⁺₂V₂O₇·2H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/n). It is a member of the Fianelite structural group.
Key properties: Mohs hardness 3; specific gravity 3.21; Orange streak; Vitreous luster; optically biaxial.
IMA symbol Fnl, IMA status: approved, named in 1995.
Found in fractures crosscutting veinlets in metamorphosed Fe–Mn ores.
It is found associated with Medaite, palenzonaite, saneroite, pyrobelonite, parsettensite, rhodochrosite, kutnohorite, aegirine, quartz.
The name refers to its occurrence in the Fianel mine, Switzerland.