Fluorkyuygenite
Fluorkyuygenite is an IMA-recognized mineral species in the halide class, with the chemical formula Ca₁₂Al₁₄O₃₂[(H₂O)₄F₂].
It crystallizes in the cubic crystal system (space group I-43d). It is a member of the Mayenite structural group.
Key properties: Mohs hardness 5–5.5; specific gravity 2.873; White streak; Vitreous luster.
IMA symbol Fky, IMA status: approved, named in 2013.
Major constituent of larnite pyrometamorphic rocks of the Hatrurim Complex (Mottled Zone). Crystallized initially as fluormayenite and was altered by vapor-enriched gases during a combustion event.
It is found associated with Larnite, shulamitite, Cr-containing spinel-magnesioferrite series, ye’elimite, fluorapatite-fluorellestadite, periclase, brownmillerite, oldhamite.
Kyuygenite is for the locality, Kyuygen-Kaya Mountain and the prefix indicates the essential fluorine in the species.