"' Eudialyte "', whose name derives from the dialytos ", meaning " well decomposable ", is a somewhat rare, nine member ring cyclosilicate mineral, which forms in alkaline igneous rocks, such as nepheline syenites.
12.
Zircon forms economic concentrations within heavy mineral sands ore deposits, within certain pegmatites, and within some rare alkaline volcanic rocks, for example the Toongi Trachyte, Dubbo, New South Wales Australia in association with the zirconium-hafnium minerals eudialyte and armstrongite.
13.
I searched a crystallography database and the highest number of elements in one compound was 22 : Johnsenite-( Ce ) of the Eudialyte group and " Ca 2 ( Y 1.53 Dy 0.10 Er 0.09 Yb 0.08 Gd 0.07 Ce 0.02 Tb 0.02 Fe 0.02 La 0.01 Nd 0.01 Sm 0.01 ( PrEu ) 0.01 Ho 0.01 Tm 0.01 Lu 0.01 ) ( ( Si 3.87 Al 0.13 ) O 12 ) CO 3 �H 2 O " from " G . Giuseppetti C . Tadini M . Oddone, " Neues Jahrbuch f�r Mineralogie.
