This study aimed to quantify the comprehensive environmental footprint of primary iridium production, a critical yet exceptionally scarce metal, to inform more sustainable practices in its supply chain. The research method employed a cradle-to-gate Life Cycle Assessment (LCA) using the Brightway2 framework, establishing a detailed inventory model for iridium production. The environmental impacts for the functional unit of 1 kg of refined iridium were evaluated using multiple impact assessment methods. Furthermore, sensitivity analysis and Monte Carlo simulations were conducted to assess parameter uncertainties. The results conclude that iridium production imposes a substantial environmental burden, particularly on climate change, with a Global Warming Potential (GWP100) of 12,009 kg CO$_2$-equivalent per kilogram. Significant impacts were also identified in the categories of ecotoxicity and human health. This study provides the first robust, probabilistic LCA of iridium, thereby offering crucial insights and a data-driven reference for producers and technology industries to mitigate the environmental impacts associated with this critical material.