Historical data have been critically compiled and analysed for investigating the quantity of nepheline (NaAlSiO4) precipitated as a function of composition in simulated nuclear waste glasses. To understand compositional effects, two primary methods were used: Investigating the Al2O3-SiO2-Na2O ternary while filtering for different B2O3 levels; and, creating a quadrant system consisting of compositions reduced to two representations: (i) the nepheline discriminator (ND) which depends only onto he SiO2 content by weight normalised to the total weight of the Al2O3-SiO3-Na2O submixture and (ii) the optical basicity (OB) which contains contributions from all constituents in the glass. Nepheline precipitation is expected to be suppressed at high SiO2 levels (ND>0.62) or at low basicities (OB
