Veins in geological reservoir settings are mineral filled fractured long being associated with the model of ‘crack seal’. However, some veins exhibit features that are difficult to explain with the model of ‘crack seal’ but would better fit with a ‘seal-crack’ model driven by the concept of crystallisation pressure. From this, two main experimental tests were conducted. First, we started with an experiment of counter diffusion to precipitate a barite front in two sedimentary rock. In fact, we did not observe damage but a barite nucleation and crystallisation behaviour linked to the pore distribution, the matrix mineral crystallisation state and an interaction between barite and clay minerals.