Gold nuggets from earthquakes

For decades, researchers have known that earthquakes, quartz, and gold were linked—nearly 75% of gold circulating today came from nuggets originally embedded in quartz deposits near faults. But in places with no clear evidence for geochemical reactions, geologist Chris Voisey says, “the conundrum is, how did we make gold in the middle of the quartz vein?” To answer this question, Voisey, a research fellow at Monash University, and his colleagues considered the unique piezoelectric properties of quartz ( Nat. Geosci. 2024, DOI: 10.1038/s41561-024 -01514-1 ). “If you strain it, it generates a voltage,” Voisey says. Quartz deposits in fault zones might experience thousands of earthquakes, Voisey says. These strain the deposits, generating piezoelectricity and creating cracks where gold-bearing water can percolate. Then, he posits, it’s a straightforward redox reaction: the excess electrons from the quartz reduce aqueous gold ions into solid gold. Once some gold is deposited, “it’ll basically become