Silicon (Si), an essential nutrient in aquatic systems and a critical component of water quality, is typically considered a geogenic solute and its riverine concentration-discharge (C-Q) relationship is often assumed to be chemostatic and controlled predominantly by discharge (i.e., small variability concentration over large range in stream discharge). However, a recent global analysis of riverine Si revealed that concentrations and loads have changed significantly over the last several decades and these changes are associated with biogeochemical processing, rather than shifts in river discharge. Consequently, assessing global patterns in Si C-Q relationships can elucidate how hydrological and biogeochemical processes are shifting and influencing the transport and cycling of Si. In this study, we analyzed the Si C-Q relationship in 467 rivers, across all seven continents, using long-term (>20 years) chemistry, discharge, and geospatial data on watershed characteristics to identify the dominant patterns of Si C-Q behavior the environmental drivers of such behavior. Specifically, we sought to evaluate watershed and climate variables that best predicted C-Q behavior, and whether the C-Q pattern or predictive variables changed over time. Our analysis revealed that most streams exhibited mobilization or dilution behavior, which was distributed across global climate zones and biome types. We evaluated the role of environmental drivers on C-Q slope using random forest models, which showed that watershed size, temperature, precipitation, and the concentrations of nitrogen and phosphorus were the best predictors of C-Q behavior. Ongoing work is evaluating shifts in Si C-Q across our >20 year dataset to understand if and how C-Q behavior has changed over time and how the control of different environmental drivers on C-Q behavior has shifted. Taken together, our study challenges the assumption that Si exhibits geogenic chemostasis, highlighting the importance of considering temporally variable C-Q behavior for predicting how Si export will change under future climate scenarios.