The damage produced by energetic ion implantation (100 keV < E < l MeV) in AgCl (single crystals or thin films) is mainly due to the Ag+sublattice. At liquid nitrogen temperature (LNT), the photographic process being blocked, the main defects created are identified as silver clusters. Their formation is analysed by means of the study of optical absorption spectra; this method permits cluster characterization with respect to elastic collision energy.