Beneath the ancient granites of South China, minerals once considered geologically indestructible are revealing a hidden vulnerability — not to the surface world, but to slow-moving hydrothermal fluids that weaken them millions of years before weathering ever begins. Researchers at the Guangzhou Institute of Geochemistry have documented how these deep, hot fluids crack open xenotime and samarskite at the nanoscale, mobilizing heavy rare earth elements critical to modern technology. The discovery does not promise an immediate abundance of new resources, but it quietly redraws the map of where s