[en] Calcium fluoride crystals doped with Gd³⁺ at four different concentrations were irradiated at room temperature. The damage produced by radiation and the primary and secondary effects as well were studied by optical spectroscopy. The increase in optical absorption (with loss of transparency) varied from sample as a function of concentration and dose. The coloration curves showed an evolution from two to three radiation damage steps when going from a pure to the most Gd³⁺ concentrated sample. The obtained spectra were analysed at characteristic wave lenghts of electronic defects (photochromic centers, F and its aggregates) and of Gd³⁺ and Gd²⁺ defects. As a result of the radiation damage the valence change (Gd³⁺→Gd²⁺) and its reversible character under thermal activation were directly observed. These effects were correlated with other observed effects such as the room temperature luminescence after the irradiation ceased. The non radiative F centers formation from the interaction of holes and photochromic centers was also observed and analysed. A thermal activation study of the several defects responsible for the different absorption bands was made. Values of activation energies were obtained as expected for the kind of defects involved in these processes