The collisional properties of ice particles determine the structure and dynamical evolution of planetary rings as well as the particle-size distribution. In this contribution, we present experimental data on the mass transfer during ice particle collisions in a laboratory environment which partially simulates the conditions in planetary rings. These data indicate that the interacting volume depends on the impact velocity. During a collision, the fraction of this volume exchanged is quite small, ∼5%; however, the net amount of material transferred may be considerably smaller. We discuss the possible implication of these data on the structure and dynamical evolution of planetary rings.