Electrical properties of annealed, fully metamict REE2Fe2+Be2Si2O10

► Alpha-decays occurring in the gadolinite structure made it more open in comparison to other non-metamict silicates due to significant fractality of the structure. ► Results presented in our work suggest that electric current relaxation in the higher temperature range is a consequence of the hydroxyl group dynamics. ► For the lower temperature range, we propose VRH of small polarons as the mechanism.