The photoluminescence properties of a silicate glass coactivated with silver and erbium ions were studied. Absorption and photoluminescence spectra allowed to distinguish in the glasses several active species related to the silver, whose ratio depends on heat treatment and silver concentration. The broad emission of silver related species in the visible region of the spectrum has been studied in correlation with the nonresonant excitation of the erbium ions. The comparison of the excitation spectra of silver and erbium shows that the erbium ions are excited through radiative and nonradiative energy transfer from small silver aggregates.