Gold is a precious metal that has always fascinated humans. From Priam’s Treasure to the legend of El Dorado, gold –regarded as the noblest of metals– has been a symbol of splendour and wealth in many civilizations. Historically, gold deposits were known to form when metal was transported dissolved by hot aqueous solution flows –hydrothermal fluids– until it accumulated in some areas in the Earth’s upper crust. The recent discovery of gold nanoparticles in such mineral deposits has brought some doubts on the validity of the classical model.