Locality: Lepkhe–Nelm Mountain, Lovozero alkaline massif, Kola Peninsula, Russia.
Occurrence: A hydrothermal mineral in cavities of a eudialyte – aegirine – feldspar pegmatite. Associated minerals are: lamprophyllite, natrolite, halloysite, ranciéite, kuzmenkoite-Zn, tsepinite-Na, vinogradovite, etc.
General appearance: Coarse, flattened prismatic crystals (up to 8 × 20 × 0.5 mm).
Physical, chemical and crystallographic properties: Luster: vitreous. Diaphaneity: translucent to transparent. Color: white, pale brown, colorless. Streak: white. Luminescence: nonfluorescent. Hardness: ~5. Tenacity: brittle. Cleavage: not observed. Fracture: uneven. Density: 2.90 g/cm3 (meas.), 2.94 g/cm3 (calc.)....