Outstanding sharp white prismatic kukisvumite crystals from the type and only known locality worldwide in Kukisvumur (Kukisvumchorr Mountains, Khibiny Massif, Murmansk Oblast, Russian Federation), and associated to lamprophyllite. Kukisvumite crystals in this quality (photo 1) are very rarely seen in the mineral market. Ex Vandenbroucke Museum collection from Waregem, Belgium — Photo: David Hospital · CC BY-SA 4.0
Kukisvumite
Kukisvumite is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₆ZnTi₄O₄(SiO₃)₈·4H₂O.
It crystallizes in the orthorhombic crystal system (space group Pccn).
Key properties: Mohs hardness 5.5–6; specific gravity 2.9; White streak; Vitreous luster; optically biaxial.
IMA symbol Kki, IMA status: approved, named in 1989.
Found in pegmatite veins cutting ijolite-urtite rocks in a differentiated alkalic massif.
It is found associated with Lamprophyllite, arfvedsonite, microcline, nepheline, natrolite.
The name refers to Mt. Kukisvumchorr, Kola Peninsula, Russia, on which it occurs.