Gold is generally associated with pyrite (iron disulfide, FeS2), and pyrite-induced gold precipitation is critical to the formation of high-grade gold deposits. However, the role of pyrite in precipitating gold from fluids has not been well understood. Now, using in situ liquid-phase transmission electron microscopy under conditions that excluded the influence of dissolved oxygen and electron beams, scientists have achieved the first nanoscale, real-time observation of the reaction between pyrite and gold-bearing solutions, providing critical insights into gold enrichment by pyrite.