Example of the paragenesis of illoqite-(Ce) with the brown ‘band’ running through the rock being weathered illoqite-(Ce). Ussingite (Usg) and chkalovite (Ckl) are marked respectively. The image is published in an open access article distributed under the terms and conditions of the Creative Commons Attribution (CC BY) license ( https://creativecommons.org/licenses/by/4.0/ ). — Photo: Emil H. Gulbransen, Henrik Friis, Fabrice Dal Bo and Muriel Erambert · CC BY-SA 4.0
Illoqite-(Ce)
Illoqite-(Ce) is an IMA-recognized mineral species in the silicate class, with the chemical formula Na₂NaBaCeZnSi₆O₁₇.
It crystallizes in the orthorhombic crystal system (space group Pcca). It is a member of the Nordite structural group.
Key properties: specific gravity 3.65; White with a faint yellow tint streak; Dull luster.
IMA status: approved, named in 2021.
Found in boulders near a large ussingite vein formed by primary magmatic processes in alkaline igneous rocks.
It is found associated with Ussingite, chkalovite, aegirine, arfvedsonite, britholite-(Ce), ancylite-(Ce), epistolite, lueshite, steenstrupine-(Ce), polylithionite.
The name commemorates the Greenlandic word illoq for “cousin”, in allusion to the relation between illoqite- (Ce) and the nordite supergroup. The suffix, Ce, indicates the dominant REE.