The detection of all of the aluminum present in steamed zeolite H-Y catalysts by Al-27 MAS NMR at 14.4 T (600 MHz for H-1) end 18.8T (800 MHz for H-1) is reported. Further, it is shown that it is possible Al MAS and MQMAS NMR measurements to clearly identify four separate aluminum environments which are characteristic of these materials and to unambiguously assign their coordinations. Average chemical shift and quadrupolar coupling parameters are used to accurately simulate the Al-27 MAS NMR spectra at 9.4 T (400 MHz for H-1), 14.4 T (600 MHz for H-1) and 18.8 T (800 MHz for H-1) in terms of these four aluminum environments. In addition, these:average chemical shift and quadrupolar coupling parameters are used to calculate peak positions in the Al-27 MQMAS isotropic dimension that are in good agreement with the experimental data acquired at 9.4 and 18.8 T.