"For three weeks, China has blocked shipments of rare-earth minerals to Japan, a move that has boosted the urgency of efforts to break Beijing's control of these minerals. China now produces nearly all of the world's supply of rare earths, which are crucial for a wide range of technologies, including hard drives, solar panels, and motors for hybrid vehicles. In response to China's dominance in rare-earths production, researchers are developing new materials that could either replace rare-earth minerals or decrease the need for them. But materials and technologies will likely take years to develop, and existing alternatives come with trade-offs."