29Si chemical shifts, δ, are for aluminosilicate zeolites expressed as δSi-4Al (which can be estimated from the T-O-T angles observed crystallographically) plus terms involving b1 and b2, the quantitative influences of first and second neighbor aluminum atoms. The former, b1, is assumed to be the sum of a fixed electrostatic component, α, and a framework-specific angular term, β(0 < β < 0.9 ppm), that reflects the generally smaller Si-O-Al angles compared to Si-O-Si. The compositional dependence of δ is approximated by an equal influence, b2, per added second neighbor aluminum atom, the concentration of which is assumed to vary linearly with composition. Values of δS-nAl; n=0-3 for representative L (LTL-framework) and omega (MAZ) zeolites calculated on this basis agree well with those observed. Applying this description of the compositional dependence to as-synthesized and dealuminated CSZ-1 zeolites enables the measurement of framework aluminum contents in this four T-site case.