Walentaite
Walentaite is an IMA-recognized mineral species in the phosphate class, with the chemical formula [Mn(H₂O)₆][ As³⁺₃Fe³⁺₃(PO₄)₂O₇].
It crystallizes in the orthorhombic crystal system (space group Imma). It is a member of the Walentaite structural group.
Key properties: Mohs hardness 3; specific gravity 2.72; Pale yellow streak; Vitreous luster; optically biaxial.
IMA symbol Wlt, IMA status: approved, named in 1983.
Found as a rare secondary mineral in a complex zoned pegmatite, probably produced through alteration of löllingite and triphylite–lithiophilite (White Elephant mine, South Dakota, USA).
It is found associated with Rockbridgeite, löllingite, spessartine, muscovite, quartz, tridymite (White Elephant mine, South Dakota, USA); pharmacosiderite, jarosite.
The mineral was named to honor Dr. Kurt Walenta (1927–), Professor of Mineralogy, University of Stuttgart, Stuttgart, Germany, for his contributions to the mineralogy of arsenates and phosphates.