Khanneshite
Khanneshite is an IMA-recognized mineral species in the carbonate class, with the chemical formula (Na,Ca)₃(Ba,Sr,Ce,Ca)₃(CO₃)₅.
It crystallizes in the hexagonal crystal system (space group P6_3mc). It is a member of the Burbankite structural group.
Key properties: specific gravity 3.8–3.9; optically uniaxial.
IMA symbol Kha, IMA status: approved, named in 1981.
Disseminated in hydrothermally-altered fine-grained carbonatite (Khanneshin complex, Afghanistan); in a drillcore in a carbonatite veinlet from a differentiated alkalic massif (Khibiny massif, Kola Peninsula, Russia).
It is found associated with Dolomite, calkinsite-(Ce), carbocernaite, mckelveyite, barite, “chlorite” (Khanneshin complex, Afghanistan); calcite, dawsonite, magnetite (Khibiny massif.
The name refers to the Khanneshin complex, Afghanistan, its first-noted occurrence.