Pale lilac crystal aggregates of the very rare Niobium mineral mongolite from the type locality in Mongolia (Dorozhnyi Pegmatite, Khanbogd District, Ömnögovi Aimag, Mongolia) and only one of the 4 localities known worldwide. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Mongolite
Mongolite is an IMA-recognized mineral species in the silicate class, with the chemical formula Ca₄Nb₆Si₅O₂₄(OH)₁₀·6H₂O.
It crystallizes in the tetragonal crystal system.
Key properties: Mohs hardness 2; specific gravity 3.147; Silky luster; optically uniaxial.
IMA symbol Mgl, IMA status: approved, named in 1983.
Found in the quartz-rich core zone of an alkalic pegmatite, as a late-stage alteration product of a niobium silicate.
It is found associated with Polylithionite, zincian montmorillonite, niobium and rare-earth silicates.
The name refers to Mongolia, the country where the mineral was discovered.