Rauchite
Rauchite is an IMA-recognized mineral species in the arsenate class, with the chemical formula Ni(UO₂)₂(AsO₄)₂·10H₂O.
It crystallizes in the triclinic crystal system (space group P-1). It is a member of the Autunite structural group.
Key properties: Mohs hardness 2; specific gravity 3.427; White streak; Vitreous, pearly on {001} luster; optically biaxial.
IMA symbol Rau, IMA status: approved, named in 2010.
A secondary mineral found in small cavities and cracks in slightly oxidized uraninite-bearing dolomite veins.
It is found associated with Dymkovite, uraninite, nickeline, gersdorffite, goethite, “limonite”, annabergite.
According to the naming rules for the autunite group as the hydrated analog of metarauchite, Ni(UO2)2(AsO4)2·8H2O - the root name honors Czech mineral collector Ludek Rauch (1951-1983).