We hereby report that ultra-high magnetic field (21.8T) solid-state nuclear magnetic resonance (NMR) spectroscopy is very useful in studies of quadrupolar nuclides in inorganic materials. The increase in signal sensitivity, especially for species with large quadrupolar products, and the decrease in signal width become significant with increasing magnetic field strength. An(27) Al 5QMAS spectrum of a refractory mortar was considerably resolved at 21.8 T compared with 16.4 T, suggesting the effectiveness of the ultra-high field NMR in clarifying the local structures in complex materials.