Formation and transformation of minerals are closely related to the interaction with melts and fluids. This interaction may modify the chemical, physical and rheological properties as well as the isotopic signatures of the involved solids. The associated mechanisms and the kinetics are strongly controlled by the physicochemical conditions at the solid-liquid interface. In this session we aim to identify those mechanisms to understand whether they are similar at mineral scale fluid-interface reaction and regional-scale rock transformation. Are the mechanisms acting at low temperatures in fluid-dominated systems fundamentally different from or even identical to those at high temperature in melt dominated ones? This session fosters an integrated discussion on low up to high temperature and pressure related processes at all scales, and documents their chemical and isotopic relevance to Earth’s chemical dynamics. We have contributions from field based, experimental and numerical geochemistry that crosslink results from various individual approaches, as well as fields of research related from (bio)geochemical to metasomatic processes in natural and man made environments.