Cesiokenopyrochlore
Cesiokenopyrochlore is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula Nb₂(O,OH)₆Cs₁₋ₓ.
It crystallizes in the cubic crystal system (space group Fd-3m). It is a member of the Pyrochlore-Pyrochlore structural group.
Key properties: Mohs hardness 5; specific gravity 5.984; Resinous luster.
IMA symbol Ckpcl, IMA status: approved, named in 2017.
From a rare-element granitic pegmatite formed by natural cation exchange with a hydrothermal solution at a late stage of pegmatite evolution.
It is found associated with Elbaite, muscovite, xenotime-(Y), pollucite, zircon, albite, kaolinite, quartz, orthoclase.
The first prefix, cesio, indicates the dominant cation at the Y site, the second prefix, keno, indicates the dominant vacancy in the A site of a member of the pyrochlore subgroup.