Chapter 1

The Most Important Solid Substance on Earth

This book is about something most of us barely ever think about and yet can't live without. It is about the most important solid substance on Earth, the literal foundation of modern civilization.

It is about sand.

Sand? Why is this humblest of materials, something that seems as trivial as it is ubiquitous, so significant?

Because sand is the main material that modern cities are made of. It is to cities what flour is to bread, what cells are to our bodies: the invisible but fundamental ingredient that makes up the bulk of the built environment in which most of us live.

Sand is at the core of our daily lives. Look around you right now. Is there a floor beneath you, walls around, a roof overhead? Chances are excellent they are made at least partly out of concrete. And what is concrete? It's essentially just sand and gravel glued together with cement.

Take a glance out the window. All those other buildings you see are also made from sand. So is the glass in that window. So are the miles of asphalt roads that connect all those buildings. So are the silicon chips that are the brains of your laptop and smartphone. If you're in downtown San Francisco, in lakefront Chicago, or at Hong Kong's international airport, the very ground beneath you is likely artificial, manufactured with sand dredged up from underwater. We humans bind together countless trillions of grains of sand to build towering structures, and we break apart the molecules of individual grains to make tiny computer chips.

Some of America's greatest fortunes were built on sand. Henry J. Kaiser, one of the wealthiest and most powerful industrialists of twentieth-century America, got his start selling sand and gravel to road builders in the Pacific Northwest. Henry Crown, a billionaire who once owned the Empire State Building, began his own empire with sand dredged from Lake Michigan that he sold to developers building Chicago's skyscrapers. Today the construction industry worldwide consumes some [...] billion worth of sand each year.

Sand lies deep in our cultural consciousness. It suffuses our language. We draw lines in it, build castles in it, hide our heads in it. In medieval Europe (and a classic Metallica song), the Sandman helped ease us into sleep. In our modern mythologies, the Sandman is a DC superhero and a Marvel supervillain. In the creation myths of indigenous cultures from West Africa to North America, sand is portrayed as the element that gives birth to the land. Buddhist monks and Navajo artisans have painted with it for centuries. "Like sands through the hourglass, so are the days of our lives," intone the opening credits of a classic American soap opera. William Blake encouraged us to "see a world in a grain of sand." Percy Bysshe Shelley reminded us that even the mightiest of kings end up dead and forgotten, while around them only "the lone and level sands stretch far away." Sand is both minuscule and infinite, a means of measurement and a substance beyond measuring.

Sand has been important to us for centuries, even millennia. People have used it for construction since at least the time of the ancient Egyptians. In the fifteenth century, an Italian artisan figured out how to turn sand into fully transparent glass, which made possible the microscopes, telescopes, and other technologies that helped drive the Renaissance's scientific revolution.

But it was only with the advent of the modern industrialized world, in the decades just before and after the turn of the twentieth century, that people really began to harness the full potential of sand and begin making use of it on a colossal scale. It was during this period that sand went from being a resource used for widespread but artisanal purposes to becoming the essential building block of civilization, the key material used to create mass-manufactured structures and products demanded by a fast-growing population.

At the dawn of the twentieth century, almost all of the world's large structures-apartment blocks, office buildings, churches, palaces, fortresses-were made with stone, brick, clay, or wood. The tallest buildings on Earth stood fewer than ten stories high. Roads were mostly paved with broken stone, or more likely, not paved at all. Glass in the form of windows or tableware was a relatively rare and expensive luxury. The mass manufacture and deployment of concrete and glass changed all that, reshaping how and where people lived in the industrialized world.

Then in the years leading up to the twenty-first century, the use of sand expanded tremendously again, to fill needs both old and unprecedented. Concrete and glass began rapidly expanding their dominion from wealthy Western nations to the entire world. At roughly the same time, digital technology, powered by silicon chips and other sophisticated hardware made with sand, began reshaping the global economy in ways gargantuan and quotidian.

Today, your life depends on sand. You may not realize it, but sand is there, making the way you live possible, in almost every minute of your day. We live in it, travel on it, communicate with it, surround ourselves with it.

Wherever you woke up this morning, chances are good it was in a building made at least partly out of sand. Even if the walls are made of brick or wood, the foundation is most likely concrete. Maybe it's also plastered with stucco, which is mostly sand. The paint on your walls likely contains finely ground silica sand to make it more durable, and may include other forms of high-purity sands to increase its brightness, oil absorption, and color consistency.

You flicked on the light, provided by a glass bulb made from melted sand. You meandered to the bathroom, where you brushed your teeth over a sink made of sand-based porcelain, using water filtered through sand at your local purification plant. Your toothpaste likely contained hydrated silica, a form of sand that acts as a mild abrasive to help remove plaque and stains.

Your underwear snapped into place thanks to an elastic made with silicone, a synthetic compound also derived from sand. (Silicone also helps shampoo make your hair shinier, makes shirts less wrinkle-prone, and reinforced the boot sole with which Neil Armstrong made the first footprint on the moon. And yes, most famously, it has been used to enhance women's busts for more than fifty years.)

Dressed and ready, you drove to work on roads made of concrete or asphalt. At the office, the screen of your computer, the chips that run it, and the fiber-optic cables that connect it to the Internet are all made from sand. The paper you print your memos on is probably coated with a sand-based film that helps it absorb printer ink. Even the glue that makes your sticky notes stick is derived from sand.

At day's end, you flopped down with a glass of wine. Guess what? Sand was used to make the bottle, the glass, and even the wine. Wine is sometimes made with a dash of colloidal silica, a gel form of silicon dioxide used as a "fining" agent to improve the beverage's clarity, color stability, and shelf life.

Sand, in short, is the essential ingredient that makes modern life possible. Without sand, we couldn't have contemporary civilization.

And believe it or not, we are starting to run out.

Though the supply might seem endless, usable sand is a finite resource like any other. (Desert sand generally doesn't work for construction; shaped by wind rather than water, desert grains are too round to bind together well.) We use more of this natural resource than of any other except air and water. Humans are estimated to consume nearly 50 billion tons of sand and gravel every year. That's enough to blanket the entire state of California. It's also twice as much as we were using just a decade ago.

Today, there is so much demand for sand that riverbeds and beaches around the world are being stripped bare of their precious grains. Farmlands and forests are being torn up. And people are being imprisoned, tortured, and murdered. All over sand.

The key factor driving our world's unprecedented consumption of this humblest of materials is this: the number and size of cities is exploding. Every year there are more and more people on the planet, and every year more and more of them move to cities, especially in the developing world.

The scale of this migration is staggering. In 1950, some 746 million people-less than one-third of the world's population-lived in cities. Today, the number is almost 4 billion, more than half of all the people on Earth. The United Nations predicts that another 2.5 billion will join them in the next three decades. The global urban population is rising by about 65 million people annually; that's the equivalent of adding eight New York Citys to the planet every single year.

To build these cities of concrete, asphalt, and glass, humans are pulling sand out of the ground in exponentially increasing amounts. The overwhelming bulk of it goes to make concrete, by far the world's most important building material. In a typical year, according to the United Nations Environment Programme, the world uses enough concrete to build a wall 88 feet high and 88 feet wide right around the equator. China alone used more cement between 2011 and 2013 than the United States used in the entire twentieth century.

There is such intense need for certain types of construction sand that places like Dubai, which sits on the edge of an enormous desert in the Arabian Peninsula, are importing sand from Australia. That's right: exporters in Australia are literally selling sand to Arabs.

What is sand, anyway? That simple syllable comprises a panoply of tiny objects of many shapes and sizes made of many different substances. As defined by the Udden-Wentworth...