Superman’s only major weakness—aside from bright red capes—is kryptonite. As luck would have it, Lex Luthor stole a sample of kryptonite labeled with jadarite’s almost exact ingredients in that summer’s Superman blockbuster. As Australia’s National Science Agency explains, jadarite contains significant amounts of the rare earth elements lithium and boron. The jadarite in Serbia remains the only known deposit of its kind, making it a highly desired piece of property. But like kryptonite, jadarite has its downsides.