A study of optical‐absorption spectra of the band of Fe2+ in the structural channels of isothermally treated beryl is reported. A linear correlation exists between the σ- and π-polarized components of the optical‐absorption spectrum at around 12000 cm-1. Irradiation with γ-rays from 60Co causes a decrease of this band. The line‐shape analysis shows two sites for Fe2+ at the structural channels. The kinetics analysis suggests a model in which Fe3+ is reduced to Fe2+ by release of holes from Fe3+ into the valence band. Subsequently, holes are retrapped by Fe2+ or annihilated by the recombination of electron and hole at a single deep trapping center. The untrapping parameter shows Arrhenius behavior. The retrapping and recombination parameters show a behavior proportional to , which is explained with a free‐electron distribution of hole velocities and a potential barrier of the trap.