Beneath hills draped in ancient rainforests, where rivers sustain millions and biodiversity flourishes, Southeast Asia hides a treasure coveted by global superpowers: rare earth elements. These minerals – neodymium, dysprosium and yttrium, to name just a few – form the backbone of modern technology, powering everything from smartphones and electric vehicles to MRI scanners and missile guidance systems. As much as one-fifth of the world’s untapped rare earth deposits are thought to nestle within...