The advanced optical and electronic characterization of primary F-defects and metallic lithium colloids in lithium fluoride thin films produced by ion-assisted thermal deposition with Xe low-energy ions (< 200 eV) on transparent amorphous substrates is presented and discussed. The volume concentrations of defects and Li nano-clusters have been estimated by applying a best-fit procedure based on a comprehensive theoretical modelling to the spectro-photometric measurements. The appreciable presence of Li metal at the film surface was clearly demonstrated by X-ray photoelectron spectra. Advanced optical microscopy confirms the negligible formation of other types of more complex luminescent colour centres.