Isolueshite Dimensions: 3 mm x 3 mm x 2 mm; Field of view: 1.30 mm Locality: Kirovskii apatite mine (Kirovsky Mine; Kirovskii Mine; Kirov Mine), Kukisvumchorr Mt, Khibiny Massif, Murmansk Oblast, Russia Collection and photograph Christian Rewitzer 5.2014 — Photo: Christian Rewitzer · CC BY-SA 3.0
Isolueshite
Isolueshite is an IMA-recognized mineral species in the oxides & hydroxide class, with the chemical formula NaNbO₃.
It crystallizes in the orthorhombic crystal system (space group Pm-3m). It is a member of the Perovskite structural group.
Key properties: Mohs hardness 5.5; specific gravity 4.72; Pale yellow streak; Adamantine luster.
IMA symbol Isl, IMA status: approved, named in 1995.
Found in a hydrothermally altered pegmatite vein in ijolite-urtite. Perhaps a quenched polymorph of lueshite, formed by rapid crystallization after a sudden drop in temperature and/or pressure.
It is found associated with Microcline, sodalite, aegirine, arfvedsonite, lamprophyllite.
Recognizes the typical isometric habit and optical isotropism in contrast to the orthorhombic polymorph lueshite.