Hatertite
Hatertite is an IMA-recognized mineral species in the arsenate class, with the chemical formula NaNaCa(Cu²⁺Fe³⁺)(AsO₄)₃.
It crystallizes in the monoclinic crystal system (space group C2/c). It is a member of the Alluaudite structural group.
Key properties: Mohs hardness 4.06; specific gravity 4.06; Yellow streak; Vitreous luster; optically biaxial.
IMA symbol Htt, IMA status: approved, named in 2012.
Forms as a sublimate at a volcanic fumarole.
It is found associated with Ponomarevite, piypite, dolerophanite, euchlorine, sylvite, lammerite, johillerite, urusovite, bradaczekite, filatovite, hematite, tenorite.
The mineral was named to honor Professor Frédéric Hatert (b. 1973), University of Liège, Belgium, for his contributions to the mineralogy and crystal chemistry of alluaudite-group minerals.