:Locality: Pegmatite No. 60, Lovozero Massif, Kola, Russian Federation Size: 1.4 × 1 × 0.7 cm Description: Manganonordite-(Ce) is a extremelly rare cerium, sodium and strontium silicate from the pegmatite 60 in Kromka stream, located in the northeastern part of the Karnasurt Mts. This pegmatite was discovered in 1955 by E.I. Semenov and it is the co-Type Locality for the species. Manganonordite-(Ce) shows a brownish radiated growths. Usually with rhabdophane-(Ce) and manganese oxides. — Photo: Joan Rosell , from rosellminerals.com · CC BY-SA 4.0
Manganonordite-(Ce)
Manganonordite-(Ce) is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₃SrCeMn²⁺Si₆O₁₇.
It crystallizes in the orthorhombic crystal system (space group Pcca). It is a member of the Nordite structural group.
Key properties: Mohs hardness 5.5; specific gravity 3.43; White streak; Vitreous, greasy on fractures luster.
IMA symbol Mnor-Ce, IMA status: approved, named in 1997.
Found in sodalite syenites and in ussingite veins in an alkaline massif.
It is found associated with Aegirine, eudialyte, sodalite, vuonnemite.
Prefix, mangano, indicates the Mn2+-dominant analog of nordite-Ce.