Langasite (La3Ga5SiO14) is a material with interesting ferroelectric and optical properties for applications in environments with high temperature and/or high ionizing radiation levels. The formation of metallic nanoclusters is, due to their unique nonlinear-optical properties, of high technological interest. The present work investigates the formation and removal of implantation-induced radiation damage as well as the production of Au-nanoparticles. Langasite single crystals were implanted with Au+ ions at an energy of 150 keV and a fluence of 1 × 1016 cm−2. The implanted samples were subjected to annealing in air at temperatures between 600 °C and 1000 °C. Optical absorption measurements indicate that stable nanoparticles are formed in the Au-implanted samples for temperatures of 800 °C and above. RBS/channeling studies show that an almost complete recovery of the crystal structure takes place. On the other hand, samples treated at 600 °C showed neither nanoparticle formation nor extended lattice recovery.