Evolution of damage in single-crystalline magnesium-aluminate spinel implanted with helium ions was studied using Rutherford backscattering technique in channeling geometry combined with surface investigation by atomic force microscopy. It was found that the damage induced by helium-ion implantation in the crystal showed significantly different annealing behavior depending on the implantation fluence. The difference in annealing behavior is ascribed to the strong dose dependence of clustering/resolution of helium atoms.