From our smartphones to our latest weaponry, the technology that underpins modern life would be impossible without rare earth metals. The importance of rare earths has only grown as emerging markets increase their demand for technologies made with it, as does the renewable energy industry. Now a new study from researchers at Yale has found that many of the materials used in high-tech products, including rare earth metals, have no satisfactory substitutes, underscoring not only our vulnerable reliance on them, but also the need to better manage these crucial resources.

Despite the name, rare earth metals—which include exotically-named elements like yttrium and dysprosium—are not in fact rare. The 17 metallic elements are common in the earth’s crust, but the techniques used to extract and refine them is labor-intensive, environmentally hazardous and increasingly costly. Thomas Gradael, a professor of geology and geophysics at the Yale School of Forestry & Environmental Studies, explains that the “criticality” of rare earths were only recently understood after China, which dominates the world’s supply of the minerals, cut exports by 40% in 2010, citing concerns over how polluting the rare earth industry was (though it maintained domestic supply levels). The subsequent price shock as the supply of the metals dropped was a wake up call for governments and those in the industry. “The challenge made people realize they had been buying materials from around the world without paying attention to where it was coming from and the geopolitical constraints affecting them,” says Gradael.