White crystal aggregates of the very rare mineral revdite from the type locality in Lovozero (Karnasurt Mountain, Lovozero Massif, Murmansk Oblast, Russian Federation), and only one of the very few localities known worldwide. Ex Vandenbroucke Museum collection from Waregem, Belgium. — Photo: David Hospital · CC BY-SA 4.0
Revdite
Revdite is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₁₆Si₁₆O₂₇(OH)₂₆·28H₂O.
It crystallizes in the monoclinic crystal system (space group C2).
Key properties: Mohs hardness 2; specific gravity 1.94; Vitreous to pearly, silky luster; optically biaxial.
IMA symbol Rev, IMA status: approved, named in 1979.
Found in ussingite veinlets cutting nepheline syenites in a differentiated alkalic massif (Lovozero massif, Russia); in sodalite xenoliths in syenite in an intrusive alkalic gabbro-syenite complex (Mont Saint-Hilaire, Canada).
It is found associated with Ussingite (Lovozero massif, Russia); ussingite, villiaumite, kogarkoite, lovozerite, eudialyte (Mont Saint-Hilaire, Canada).
The name refers to Revda, a town near Mt. Karnasurt, on which the mineral occurs.