Sand

From the New Yorker - The World is Running Out of Sand:

"Pascal Peduzzi, a Swiss scientist and the director of one of the U.N.’s environmental groups, told the BBC last May that China’s swift development had consumed more sand in the previous four years than the United States used in the past century. In India, commercially useful sand is now so scarce that markets for it are dominated by “sand mafias”—criminal enterprises that sell material taken illegally from rivers and other sources, sometimes killing to safeguard their deposits. In the United States, the fastest-growing uses include the fortification of shorelines eroded by rising sea levels and more and more powerful ocean storms—efforts that, like many attempts to address environmental challenges, create environmental challenges of their own."