We present high (> 2 T) magnetic field βNMR measurements of ⁸Li⁺ implanted in single crystals of sapphire, a commonly used backing material for other samples. From the well-resolved quadrupolar splitting, we extract the electric field gradient (EFG) at the implanted ⁸Li⁺ site. Comparison with supercell density functional theory calculations of the EFG allows us to identify the octahedral interstitial site as the most likely candidate. In contrast to the zero field βNQR spectra, where multiple singals are detected, only a single site is evident at high field. We discuss possible explanations for this discrepancy. The spin lattice relaxation is extremely slow (1/T₁ < 0.02 s⁻¹ ) over a broad temperature range from 4 to 300 K, demonstrating that cross relaxation with the ²⁷Al nuclear spins is quenched in such high magnetic fields.