Apart from water and air, humble sand is the natural resource most consumed by human beings. People use more than 40 billion tons of sand and gravel every year. There’s so much demand that riverbeds and beaches around the world are being stripped bare. (Desert sand generally doesn’t work for construction; shaped by wind rather than water, desert grains are too round to bind together well.) And the amount of sand being mined is increasing exponentially.
Though the supply might seem endless, sand is a finite resource like any other. The worldwide construction boom of recent years—all those mushrooming megacities, from Lagos to Beijing—is devouring unprecedented quantities; extracting it is a $70 billion industry. In Dubai enormous land-reclamation projects and breakneck skyscraper-building have exhausted all the nearby sources. Exporters in Australia are literally selling sand to Arabs.
It's a crazy, crazy world.