metarauchite

{{Infobox mineral|name=Metarauchite|boxwidth=|boxbgcolor=|image=Metarauchit-345903.jpg|imagesize=|alt=|caption=Metarauchite|category=Uranyl Arsenates|formula=Ni(UO2)2(AsO4)2·8H2O| IMAsymbol = Mrau|molweight=|strunz=08.EB.05|dana=40.02a.17.02|system=Triclinic|class=Pinacoidal H-M symbol: |symmetry=P|unit cell=a = 7.194(4) b = 9.713(5) c = 13.201(9) α = 75.79(5)° β = 83.92(3)° γ = 81.59(4)°|color=Yellow to light greenish yellow|colour=|habit=Tabular crystals|twinning=Multiply twinned along {011}|cleavage=Perfect on (011)|fracture=Uneven|tenacity=Very brittle|mohs=2|luster=Vitreous – pearly|streak=Light green to pale yellow|diaphaneity=Transparent to translucent|gravity=|density=3.81 gm/cc|polish=|opticalprop=Biaxial (−)|refractive=|birefringence=δ = 0.024|pleochroism=Non-pleochroic|2V=Measured: 23–52°|dispersion=|extinction=|length fast/slow=|fluorescence=None|absorption=|melt=|fusibility=|diagnostic=|solubility=Cold 10% HCl|impurities=|alteration=|other=|references=}} Metarauchite is a member of the autunite group, found at the Jáchymov ore district (type locality), Czech Republic and in Schneeberg, Germany. The autunite group is a group of structured uranyl phosphates and arsenates; the other members of the group are autunite, bassetite, heinrichite, kahlerite, nováčekite-I, nováčekite-II, rauchite, sabugalite, saléeite, torbernite, uranocircite, uranospinite, and zeunerite. The mineral is named after Czech mineral collector Luděk Rauch, who died in the Jáchymov mines during mineral prospecting.

== Occurrence == Metarauchite occurs as a secondary mineral in strongly oxidized polymetallic vein material. Metarauchite is found primarily in two localities, the northern part of the Jáchymov ore district, northwestern Bohemia, Czech Republic and the Heber mine, Neustädtel, Germany. It is commonly associated with metazeunerite, erythrite, and gypsum (Jáchymov) and Ni-bearing metanováčekite, metazeunerite, pharmacosiderite (Schneeberg). Both localities have a surface containing strongly altered aggregates of primary ore with relics of uraninite, arsenopyrite and nickelskutterudite and traces of native bismuth at the Schweitzer vein in the Eduard mine.