Vapnikite
Vapnikite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Ca₂CaUO₆.
It crystallizes in the monoclinic crystal system (space group P2_1/n). It is a member of the Perovskite structural group.
Key properties: Mohs hardness 5; specific gravity 5.322; Yellowish white streak; Strongly vitreous luster; optically biaxial.
IMA symbol Vpn, IMA status: approved, named in 2013.
Found in the Hatrurim Formation (“Mottled Zone”). Formed by pyrometamorphism due to combustion of organic-rich material at temperatures above 800 flC., during a retrograde stage by fluids/melts of high alkalinity.
It is found associated with Larnite, brownmillerite, ye’elimite, vorlanite, fluorellestadite.
The mineral was named to honor Yevgeny Vapnik of Ben Gurion, University of the Negev, Beer Sheva, Israel, for his mineralogical studies of the Hatrurim Formation.