Flinkite
Flinkite is an IMA-recognized mineral species in the arsenate class, with the chemical formula Mn²⁺₂Mn³⁺(AsO₄)(OH)₄.
It crystallizes in the orthorhombic crystal system (space group Pnma). It is a member of the Allactite structural group.
Key properties: Mohs hardness 4.5; specific gravity 3.87; Vitreous, resinous to somewhat greasy luster; optically biaxial.
IMA symbol Fln, grandfathered status — known before the IMA’s founding, named in 1889.
Very rare, in veinlets in magnetite ore (Harstigen mine, Sweden); in a metamorphosed stratiform zinc orebody (Franklin, New Jersey, USA).
It is found associated with Sarkinite, brandtite, caryopilite, nadorite, lead, manganoan calcite, barite (Harstigen mine, Sweden); cahnite, jarosewichite, franklinite, hausmannite.
The mineral was named to honor Gustav Flink (1849–1931), Swedish mineralogist and collector.