WALPURGITE
Class : Phosphates, arsenates, vanadates
Subclass : Hydrated arsenates
Crystal system : Triclinic
Chemistry : Bi4(UO2)O4(AsO4)2 2H2O
Rarity : Rare
Walpurgite is a rare secondary mineral from the oxidation zone of hydrothermal deposits containing bismuth, uranium and arsenic. It owes its name to its discovery location : the Walpurgis vein of the Weisser Hirsch mine (Germany). Walpurgite forms elongated lamellar crystals, grouped in radiate bundles or in subparallel aggregates not exceeding 6 mm, of a wax yellow to straw yellow color, sometimes colorless.
Main photo : Walpurgite from Schmiedestollen dump, Wittichen, Germany © Uwe Haubenreisser
Walpurgite in the World
Fakes and treatments
No fakes listed for this mineral species.
Hardness : 3.5
Density : 6.59
Fracture : Undetermined
Streak : Brown-yellow
TP : Translucent to transparent
RI : 1.871 to 2.050
Birefringence : 0.134 to 0.150
Optical character : Biaxial -
Pleochroism : Low
Fluorescence : None
Solubility : -
Magnetism : NoneRadioactivity : Medium