Orange brown microcrystals of the extremely rare Ca-Fe arsenate mineral wallkilldellite-(Fe) from the type locality in Roua mine (Daluis, Alpes-Maritimes, Provence-Alpes-Cote d'Azur, France), and one of the only 5 localities known worldwide. Much rarer than the Mn term, from the elusive type locality hidden in a canyon in the Southern French Alps. Ex Dr.Hartel collection, Ex Ch.Rewitzer collection. — Photo: David Hospital · CC BY-SA 4.0
Wallkilldellite-(Fe)
Wallkilldellite-(Fe) is an IMA-recognized mineral species in the arsenate class, with the chemical formula Ca₂Fe²⁺₃(AsO₄)₂(OH)₄·9H₂O.
It crystallizes in the hexagonal crystal system.
Key properties: Mohs hardness 2–3; specific gravity 3; Light brown streak; Vitreous on cleavage surfaces; slightly resinous on fracture surfaces luster; optically uniaxial.
IMA symbol Wlk-Fe, IMA status: approved, named in 1997.
Secondary in the oxidation zone of copper arsenide deposits.
It is found associated with Cuprite, native copper and silver, algodonite, domeykite, koutekite, olivenite, kolfanite, janggunite, malachite (Roua mine); arsenopyrite, yukonite.
The suffix, Fe, indicates the iron analog of wallkilldellite.