Rhenium (Re) and Osmium (Os) have been used as geochemical tracers and have provided geoscientists with context for global changes in weather and climate throughout Earth’s history [1, 2]. However, very little is known about these rare elements. A critical question is how the adsorption of dissolved Os and Re onto clay minerals changes during salinity transitions. This research investigates this adsorption process under four salinity conditions. These data could provide insight on Rhenium and Osmium’s role in mineral weathering reactions that are related to the carbon cycle occurring on both long geologic and short human timescales.