Gold nuggets occur predominantly in quartz veins, and the current paradigm posits that gold precipitates from dilute (<1 mg kg⁻¹ gold), hot, water ± carbon dioxide-rich fluids owing to changes in temperature, pressure and/or fluid chemistry. However, the widespread occurrence of large gold nuggets is at odds with the dilute nature of these fluids and the chemical inertness of quartz. Quartz is the only abundant piezoelectric mineral on Earth, and the cyclical nature of earthquake activity that drives orogenic gold deposit formation means that quartz crystals in veins will experience thousands of episodes of deviatoric stress. Here we use quartz deformation experiments and piezoelectric modelling to investigate whether piezoelectric discharge from quartz can explain the ubiquitous gold–quartz association and the formation of gold nuggets. We find that stress on quartz crystals can generate enough voltage to electrochemically deposit aqueous gold from solution as well as accumulate gold nanoparticles. Nucleation of gold via piezo-driven reactions is rate-limiting because quartz is an insulator; however, since gold is a conductor, our results show that existing gold grains are the focus of ongoing growth. We suggest this mechanism can help explain the creation of large nuggets and the commonly observed highly interconnected gold networks within quartz vein fractures.

金块主要出现在石英脉中，目前的范式认为，由于温度、压力和/或流体化学的变化，金从稀（<1 mg kg ^-1金）、热水±富含二氧化碳的流体中沉淀出来。然而，大金块的广泛存在与这些流体的稀释性质和石英的化学惰性相矛盾。石英是地球上唯一丰富的压电矿物，而驱动造山金矿形成的地震活动的周期性意味着矿脉中的石英晶体将经历数千次偏应力。在这里，我们使用石英变形实验和压电建模来研究石英的压电放电是否可以解释普遍存在的金-石英关联和金块的形成。我们发现石英晶体上的应力可以产生足够的电压，以电化学方式从溶液中沉积金水溶液并积累金纳米颗粒。由于石英是绝缘体，因此通过压电驱动的反应使金成核受到速率限制。然而，由于金是导体，我们的结果表明现有的金颗粒是持续增长的焦点。我们认为这种机制可以帮助解释大金块的形成以及石英脉裂缝中常见的高度互连的金网络。