Nepheline syenite is an aluminium silicate consisting of minerals nepheline, microcline and albite. A quartz-free feldspathoid, nepheline syenite is commonly reported together with feldspars but has a ...

The radioelement-bearing pegmatite is characterized by aggregates of black biotite interstitial to feldspars and quartz. The biotite aggregates are the loci for very fine-grained euhedral uraninite ...