2D Al TQ/MAS NMR experiments were set up using kyanite as a model system and carried out at 20 kHz MAS frequency with 2 s delays and 1 H SPINAL64 decoupling. The standard z-filtered three-pulse sequence with excitation, reconversion, and selective pulse lengths of 4.2, 1.5, and 43.0 µs, respectively, was used. The z-filter pulse length was 20 µs. All Al ssNMR chemical shifts were referenced externally to aqueous [Al(H 2 O) 6 ] 3+ (δ = 0.0 ppm).