Water is a major component of fluids in the Earth’s mantle, where its properties are substantially different from those at ambient conditions. The reactions that occur at the mineral-water interface are central to all geochemical processes. They affect a wide range of important processes, all of which involve geochemical element recycling. To better understand the interactions between rocks, minerals and H2O-bearing fluids, we seek contributions that provide new experimental and theoretical data, or results from field studies from crustal to deep mantle conditions. Topics of interest include but are not limited to the structural and physical properties of dense H2O-bearing fluids and melts, their chemical and solvent properties, the distribution and movement of mantle fluids, mineral solubility, the speciation of solutes, and the partitioning of elements between fluids and minerals or rocks in the Earth’s interior, weathering and soil formation, nutrient availability, biomineralization, acid mine drainage, the fate of contaminants, element partitioning during mineral growth. We invite novel contributions from petrology, mineral physics, seismology, trace element/isotope geochemistry and modelling that expand our understanding of fluid-rock interactions from the deep Earth to the surface.