Recent research has unveiled a groundbreaking connection between earthquakes and the formation of massive gold nuggets in quartz. Scientists propose that seismic activity generates an electric field that can attract gold dissolved in fluids, which emerge from deep underground.
These astonishing gold nuggets, often found alongside quartz—a common but chemically inert mineral—can weigh nearly 100 kilograms. Previously, the process behind their formation remained elusive.
“The challenge has been to understand how such large gold nuggets form in a specific location without clear chemical or physical traps,” states a researcher from Monash University in Melbourne.
The research team has identified that when quartz experiences pressure, it generates a voltage capable of attracting gold that is dissolved in water. The unique structure of quartz is key to this phenomenon. Unlike other abundant minerals, quartz lacks a center of symmetry in its crystal structure, allowing it to produce electricity when subjected to mechanical stress, a phenomenon known as piezoelectricity.
During seismic events, gold-bearing hydrothermal fluids from depths of 15 to 20 kilometers are pushed through cracks in the Earth’s crust. However, the concentration of gold in these fluids is extremely low—requiring the volume of five Olympic swimming pools to extract just 10 kilograms of gold.
The researchers theorized that repeated earthquakes could concentrate gold into nuggets through the piezoelectric effects of quartz. Experiments revealed that quartz crystals exposed to pressure attracted more gold compared to those that weren’t. Notably, samples coated with iridium demonstrated enhanced piezoelectric responses, leading to the formation of larger gold particles measuring upwards of 6000 nanometers versus merely 200 to 300 nanometers for uncoated quartz.
Once gold begins to deposit on quartz, it rapidly attracts additional gold particles. “Gold, being a conductor, significantly increases the likelihood of additional gold in solution depositing onto existing gold,” the researcher explains. “It effectively acts like a lightning rod, drawing in more gold.”
