Arsenuranospathite


Arsenuranospathite is a rare mineral with the chemical formula Al22F·20H2O. The name "arsenuranospathite" as arsenate analog of uranospathite was first used by Walenta with reference to a uranyl-arsenate mineral from Black Forest massif, Germany.
Later it was undoubtedly demonstrated that the name arsenuranospathite was applied, at least, to two different species – proper arsenuranospathite, ideally Al22F·20H2O, orthorhombic, and its partially dehydrated analogue, Al22F·nH2O, tetragonal or pseudo-tetragonal.

Properties

Yellow to yellow-greenish, transparent to opaque tabular and prismatic crystals, with perfect cleavage. Transparent to translucent. Hardness = ∼2. Radioactive.

Chemical composition

Contents of Al and U are very stable. Main variations of chemical compositions are connected with the ratio As:P and the content of F.

Occurrences

Sophia Mine, Böckelsbach valley, Wittichen, Schenkenzell, Black Forest, Baden-Württemberg, Germany