Pyrite is the major sulfide mineral on Earth hosting a plethora of precious and critical trace metals. They are often coupled with thallium that might act as ore pathfinder. On the other hand, the presence of Tl, a harmful pollutant, strongly devaluates sulfide ore and poses environmental threat. To manage such metal resources, we need to know the speciation of trace elements in the mineral to understand their genetic relationships and mechanisms of coupled uptake and release. Here, we will use high-energy resolution fluorescence detection X-ray absorption spectroscopy to determine the structural and redox state of both Tl and Au in the same samples of pyrite from ore deposits and their synthetic analogues prepared at controlled laboratory conditions. This experiment will allow the factors controlling common Au and Tl enrichment in and release from pyrite to be identified. The data will help more efficient and safe prospection and treatment for gold and associated critical metals.