Lithium exploration and production have been steadily increasing over the past decade due to lithium’s favorable ratio of molecular-mass-to-energy-density, making lithium well suited for battery manufacturing. Batteries are a necessary technology to enable a transition of our current carbon-based energy infrastructure towards one composed of a higher proportion of renewable sources. Lithium has traditionally been obtained from lithium-brine deposits and from a handful of spodumene deposits. Since lithium has not been extensively mined from hard rock deposits in the past, there is little information on the potential negative impacts of increasing the hard rock production of lithium in order to meet the current lithium demand. This thesis aims to provide necessary information regarding the environmental geochemistry of hard rock lithium deposits. It consists of a water and rock sampling and characterization study, an experimental leaching study, and an experimental study investigating the role clay precipitation has on removing lithium from aqueous solution. We sampled surface waters near four deposits in Central Europe, namely Cínovec on the border of the Czech Republic and Germany, Podlesí and Homolka in the Czech Republic, and Sankt Radegund bei Graz in Austria. We analyzed those aqueous samples for their chemical composition to estimate background concentration of lithium and other major elements found in surface waters near lithium-rich rocks. We also thoroughly investigated the geological samples from each location, discovering a rare Fe-Mn-phosphate mineral – childrenite – and providing its structural and compositional data, which are sparse in the literature. We then subjected the rocks from these, as well as other, sites to solutions that approximate acid rain and organic acids found in soils, as well as double deionized water equilibrated with CO2 in air. This experiment allowed us to determine the leaching potential of lithium and other ions from these rocks in readily available environmental solutions. We also create a method to analyze the lithium isotope evolution on a triple-quadrupole-inductively-coupled-plasma-mass-spectrometer over the course of our leaching experiments to better approximate the fate of lithium once in solution. In the field study, we observed slightly elevated lithium concentrations relative to background values as well as high fluorine and aluminum concentrations, which are environmental and health hazards. We verify these findings in our laboratory leaching experiments, while observing the ease with which lithium is released from lithium-rich micas. Finally, during our lithium isotope investigations, we find evidence of secondary mineral precipitation and a removal of lithium from the solution. This lithium is likely being incorporated into secondary minerals, such as clays, highlighting a potential natural remediation process for the lithium. However, this process does not seem to operate on the same order of magnitude as the dissolution of the crushed primary lithium micas used in the study. We also challenge a long-held assumption that there is no-to-little lithium isotope fractionation during primary mineral dissolution, as our data highlight fractionation due to zinnwaldite, and to a lesser degree, lepidolite, dissolution. This fractionation is likely being driven by faster kinetic diffusion of 6Li relative to 7Li and increasing coordination number of lithium in acidic aqueous solutions.