During water-rock interaction, several processes occur: coupled dissolution-reprecipitation, open-system reaction with formation of a compositionally different mineral, and Fick's Law diffusion in an inert matrix. All of these processes modify the stable and radiogenic isotopic compositions of the minerals. This paper reviews the diagnostic potential of the microtextural and petrological constraints, which help to quantitatively constrain the rates of the processes affecting the radiogenic isotopes used in geochronology.