Occurs intergrown with zirsilite-(Ce) in a cavity near the margin of a marble xenolith in an igneous breccia along the contact between porphyritic nepheline syenite and sodalite sye nite. Eudialyte group
Approved IMA 2004 (Dana # Added)
Poudrette Quarry, Mont Saint-Hilaire, Rouville County, Quebec, Canada Link to MinDat.org Location Data.
Named for Ole Johnsen (b. 1940), of the Geological Museum, University of Copenhagen, Denmark, and for his extensive research into the eudialyte group.