The World in a Grain

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 $130 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 scale, the most commonly used geologic standard, the term sand encompasses loose grains of any hard material with a diameter between 2 and 0.0625 millimeters. That means the average grain of sand is a tad larger than the width of a human hair. Those grains can be made by glaciers grinding up stones, by oceans degrading seashells and corals (many Caribbean beaches are made of decomposed shells), even by volcanic lava chilling and shattering upon contact with air or water. (ThatÕs where HawaiiÕs black sand beaches come from.)

Nearly 70 percent of all sand grains on Earth, however, are quartz. These are the ones that matter most to us. Quartz is a form of silicon dioxide, or SiO2, also known as silica. Its components, silicon and oxygen, are the most abundant elements in the Earth's crust, so it's no surprise that quartz is one of the most common minerals on Earth. It is found abundantly in the granite and other rocks that form the world's mountains and other geologic features.

Most of the quartz grains we use were formed by erosion. Wind, rain, freeze-thaw cycles, microorganisms, and other forces eat away at mountains and other rock formations, breaking grains off their exposed surfaces. Rain then washes those grains downhill, sweeping them into rivers that carry countless tons of them far and wide. This waterborne sand accumulates in riverbeds, on riverbanks, and on the beaches where the rivers meet the sea. Over the centuries, rivers periodically overflow their banks and shift their courses, leaving behind huge deposits of sand in what has become dry land. Quartz is tremendously hard, which is why quartz grains survive this long, bruising journey intact while other mineral grains disintegrate.

Over millions of years, sands are often buried under newer layers of sediment, uplifted into new mountains, then eroded and transported once again. "Sand grains have no souls, but they are reincarnated," writes geologist Raymond Siever in his book Sand. "Each cycle of deposition, burial, uplift and erosion renews the sand grains and rounds each grain a little more." The average time for this cycle is 200 million years. The next time you dump sand out of your shoes, give those grains a little respect: they may predate the dinosaurs.

In the wild, quartz always comes mixed with bits of other materials: iron, feldspar, whatever other minerals prevail in the local geology. (Pure quartz is transparent, but quartz grains are often stained by oxidation. That coloring, plus the presence of other types of grains, is why most beaches and sand deposits you see are various shades of yellow or brown.) A certain amount of those other substances need to be filtered out before the sand can be used to make concrete, glass, or other products.

You can think of sand sort of like a colossal army, or a group of related armies, made up of quintillions of tiny soldiers. Only these armies are deployed not to kill, but to create. Rather than destroy, these soldiers build structures and products and perform services for us.

At first glance, sand grains, like uniformed troops, all look pretty much the same. In fact, though, there are many different types, with different attributes, strengths, and weaknesses, which in turn determine the uses to which they can be put. Some are prized for their hardness, some for their pliancy; some for their roundness, some for their angularity; some for their color, some for their purity. Some sands, like specially chosen commandos, are put through elaborate physical or chemical processes to alter their capabilities, or are combined with other materials to perform tasks they could not in their original state.

Construction sand-the hard, angular grains used primarily to make concrete-are the infantry of this army. This kind of sand is abundant, easily found, and not especially pure. Its grains are mainly quartz, but include other minerals, which vary depending on where the sand was mined. Construction sand can be found in virtually every country, often mixed with its indispensable partner, gravel. The construction industry refers to sand and gravel together as aggregate; the difference between sand and gravel is mainly just size. These particles are drafted into service from riverbeds, beaches, or land quarries. Sand and gravel aggregates are put to work together to make concrete, while sand is deployed on its own to make other construction materials like mortar, plaster, and roofing components.

Marine sands-the naval wing of the army, found on the ocean floor-are of similar composition, making them useful for artificial land building, such as Dubai's famous palm-tree-shaped man-made islands. These underwater grains can also be used for concrete, but that requires washing the salt off them-an expensive step most contractors would rather avoid.

Silica sands are purer-at least 95 percent silica-and are found in fewer places than construction or marine sand. Also called industrial sands, they're the Special Forces of the sand army, capable of being put to more sophisticated purposes than the average foot soldier. These are the sands you need to make glass. Higher-purity sands are especially prized: the sands of north-central France's Fontainebleau region, for instance, are upward of 98 percent pure silica. Europe's finest glassmakers have relied on them for centuries. Silica sands are also used to help make molds for metal foundries, add luster to paint, and filter the water in swimming pools, among many other tasks. Some of the unique properties of industrial sands suit them for highly specific jobs. The silica sands of western Wisconsin, for instance, have a particular shape and structure that make them ideal for use in fracking for oil and gas.