"A riverboat captain, wanting to put his passengers at ease, said, 'I’ve sailed boats on this river for so long, I know where each sandbar is.'But suddenly, the boat struck a sandbar so hard, it shook the boat and all the passengers. 'Look,' he said, 'there’s one of them now!' the Moon began to talk when her light was reflected by the tide at downstream, after previously greeting with Basmalah and Salaam.
"Sand," the Moon continued, "something that seems as trivial as it is ubiquitous, the humblest materials but a solid substance on Earth, the main material by way of modern cities are made as well as the literal foundation of modern civilization.
Perhaps the only place where most people really appreciate sand—or even think about it—is the beach. But not only that, in fact, 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.
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. 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.
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, a cosmic being who controls all dreams, 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. Sand is both minuscule and infinite, a means of measurement and a substance beyond measuring.
All of this, happened when the advent of the modern industrialized world exist, 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.
What is sand, anyway? F. J. Pettijohn, Paul Edwin Potter, Raymond Siever, all of then are Professors of Geology, say that Sand is loose, non-cohesive granular material, the grains or framework elements of which must by definition be sand-sized. Various attempts have been made to define sand more precisely. These attempts are largely directed toward expressing grain size in terms of grain 'diameter' of some specified magnitude.
In as much as sand grains are non-regular solids, it is first necessary to define the term 'diameter' as applied to such solids. Attempts to codify the meaning of 'sand' as a size-term are many. The effort to do so is usually part ofa larger effort to codify all size terms and to construct a 'grade scale'. The various choices made for the size class 'sand' in some of these grade scales. We shall here adopt the diameter limits 0.0625 (1/16) and 2.0 mm for 'sand'—limits which have become generally accepted among sedimentologists.
The Udden-Wentworth scale, defined 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—that’s where Hawaii’s 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.14 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.
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. Construction sand can be found in virtually every country, often mixed with its indispensable partner, gravel.
Silica sands are purer—at least 95 percent17 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.
For the most part, we don’t draft desert sands into our service. The grains found in deserts are mostly too round to use for construction. The reason is that wind is harsher than water. In a river, water cushions the impact of the grains tumbling against one another. In a desert, they just bang full force into one another, rounding off their corners and angles.
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. Concrete is an invention as transformative as fire or electricity. It has changed where and how billions of people live, work, and move around. Concrete is the skeleton of the modern world, the scaffold on which so much else is built. It gives us the power to dam enormous rivers, erect buildings of Olympian height, and travel to all but the remotest corners of the world with an ease that would astonish our ancestors. Measured by the number of lives it touches, concrete is easily the most important man-made material ever invented.
This world-transforming substance is composed mainly of the simplest, most commonplace ingredients: gravel and sand. Concrete, in fact, is the primary driver of the global sand crisis; we use far more sand to make concrete than for any other purpose. Billions of tons of sand and gravel are unearthed every year and pressed into service to form shopping malls, freeways, dams, and airports. The whole substrate of the world we live in rests on the shoulders of that vast infantry of miniature stones.
All of which is even more amazing when you consider that only a little over a century ago, we barely used concrete at all.
Let’s clear up one thing right away: Cement is not the same thing as concrete. Cement is an ingredient of concrete. It’s the glue that binds the gravel and sand together. Cements (there are many forms) are typically made by crushing up clay, lime, and other minerals, firing them in a kiln at temperatures up to 2,700 degrees, then milling the result into a silky-fine gray powder. Mix that powder with water and you get a paste. The paste doesn’t simply dry, like mud; it “cures,” meaning the powder’s molecules bond together via a process called hydration, its chemical components gripping each other ever tighter, making the resulting substance extremely strong. Reinforced with a platoon of sand, that paste thickens into mortar, the stuff used to hold bricks together.
Though concrete is the quintessential modern building material, people in several places over the centuries have stumbled on the trick of making it. The Mayans, who flourished 2,000 years ago in what is now southern Mexico, Guatemala, and Belize, made crude concrete beams to support some of their buildings. The Greeks used cement mortars. (Some scholars believe the ancient Egyptians used a form of concrete in the building of pyramids, though most disagree. The Egyptians almost certainly did use sand, though, to help their bronze saws cut through stone for their monuments, likely including the pyramids. Sand, in fact, has been used for construction since at least 7000 BCE, by ancient peoples who mixed it with mud to make crude bricks.) But by far the most enthusiastic and technically sophisticated users of concrete in the ancient world were the Romans. But it’s not clear exactly when or how the Romans figured out the secret of concrete making.
The Romans built houses, shops, public buildings, and baths from concrete. The breakwaters, towers, and other structures that made up the colossal man-made harbor of Caesarea, in what is now Israel, were built with concrete, as was the foundation of the Colosseum, along with countless bridges and aqueducts across the empire. Most famously, Rome’s Pantheon, built nearly 2,000 years ago, is roofed with a spectacular concrete dome—still the biggest concrete structure without reinforcing steel in the 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, to tell your subordinate, who arrived late, that 'I'm here,' is derived from sand.
At day’s end, you flopped down with a cup of tea, or maybe, 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 of sands.
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.
Armies of sand have built our cities, paved our roads, shown us distant stars and subatomic particles, spawned the Internet, and made our way of life possible. But extracting and deploying them on the immense scale of the twenty-first century has also brought destruction and death. On the next session, we'll talk about how sand mining develops. Bi idhnillah."
