The chemistries of the Stjerni:iy and Blue Mountain nepheline syenites are compared. They both belong to the miascitic type of nepheline syenites. They have low concentrations of the rare earths, scandium, yttrium, niobium, uranium, and thorium. They have a characteristically high K/Rb ratio (> 500), and are very Iow in Cs. Their major chemical difference is in the K/Na ratio and the Ba and Sr concentrations. The Stjerni:iy nepheline syenite crystallized at the higher temperature. Both are used in the ceramics industries.