Bendadaite Locality: Almerindo mine, Linópolis, Divino das Laranjeiras, Minas Gerais, Brazil Description: Picture width 2.5 mm. Collection and photograph Christian Rewitzer — Photo: Christian Rewitzer · CC BY-SA 3.0
Bendadaite
Bendadaite is an IMA-recognized mineral species in the arsenate class, with the chemical formula Fe²⁺Fe³⁺₂(AsO₄)₂(OH)₂·4H₂O.
It crystallizes in the monoclinic crystal system (space group P2_1/c). It is a member of the Arthurite structural group.
Key properties: Mohs hardness 3; specific gravity 3.15; Greenish yellow streak; Vitreous to sub-adamantine luster; optically biaxial.
IMA symbol Bdd, IMA status: approved, named in 1998.
From the dumps of phosphate-bearing columbite-beryl pegmatite; a secondary (or late- hydrothermal) mineral with Fe and As derived from weathered arsenopyrite.
It is found associated with Scorodite-mansfieldite, gypsum (Bendada); albite, muscovite, quartz, schorl, elbaite, löllingite, scorodite, pharmacosiderite, saléeite, phosphuranylite.
The name refers to the occurrence in Portugal at Bendada.