by Vince Beiser
In the twentieth century, concrete, asphalt, and glass utterly transformed the built environment for countless millions in the Western world. Armies of sand brought us skyscrapers and suburbs, windows and bottles for everyone, and the paved roads that the automobile depends on. In the twenty-first century, that sand-based way of life is spreading with blinding speed across the entire world.
In this new era, the sand armies are taking on even more world-changing missions. Sand is now being used to build entire new lands, to pull oil from previously inaccessible pockets of the earth, and to create the digital devices that permeate our lives. A century and a half ago, sand was a useful accessory, a handy tool for a handful of purposes. Today our civilization depends on it.
PART II
How Sand Is Building the Twenty-First Century’s Globalized, Digital World
And every one that heareth these sayings of mine, and doeth them not, shall be likened unto a foolish man, which built his house upon the sand.
—MATTHEW 7:26
CHAPTER 5
High Tech, High Purity
Fresh from church on a cool, overcast Sunday morning in Spruce Pine, North Carolina, Alex Glover slid onto the plastic bench of a McDonald’s booth. He rummaged through his knapsack, then pulled out a plastic sandwich bag full of white powder. “I hope we don’t get arrested,” he said. “Someone might get the wrong idea.”
Glover is a recently retired geologist who has spent decades hunting for valuable minerals in the hillsides and hollows of the Appalachian Mountains that surround this tiny town. He is a small, rounded man with little oval glasses, a neat white mustache, and matching hair clamped under a Jeep baseball cap. He speaks with a medium-strength drawl that emphasizes the first syllable and stretches some vowels, such that we’re drinking CAWWfee as he explains why this remote area is so tremendously important to the rest of the world.
Spruce Pine is not a wealthy place. Its downtown consists of a somnambulant train station across the street from a couple of blocks of two-story brick buildings, including a long-closed movie theater and several empty storefronts.
The wooded mountains surrounding it, though, are rich in all kinds of desirable rocks, some valued for their industrial uses, some for their pure prettiness. But it’s the mineral in Glover’s bag—snowy white grains, soft as powdered sugar—that is by far the most important these days. It’s our old friend quartz, but not just any quartz. Spruce Pine, it turns out, is the source of the purest natural quartz ever found on Earth. This ultra-elite corps of silicon dioxide particles plays a key role in manufacturing the silicon used to make computer chips. In fact, there’s an excellent chance the chip that makes your laptop or cell phone work was made using quartz from this obscure Appalachian backwater. “It’s a billion-dollar industry here,” said Glover with a hooting laugh. “Can’t tell by driving through here. You’d never know it.”
In the twenty-first century, sand has become more important than ever, and in more ways than ever. This is the digital age, in which the jobs we work at, the entertainment we divert ourselves with, and the ways we communicate with one another are increasingly defined by the Internet, and the computers, tablets, and cell phones that connect us to it. None of this would be possible were it not for sand. High-purity silicon dioxide particles are the essential raw materials from which we make computer chips, fiber-optic cables, and other high-tech hardware—the physical components on which the virtual world runs. The quantity of quartz used for these products is minuscule compared to the mountains of it used for concrete or land reclamation. But its impact is immeasurable.
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Spruce Pine’s mineralogical wealth is thanks to the area’s unique geologic history. About 380 million years ago the area was located south of the equator. Plate tectonics pushed the African continent toward eastern America, forcing the heavier oceanic crust—the geologic layer beneath the ocean’s water—down underneath the lighter North American continent. The friction of that colossal grind generated heat topping 2,000 degrees Fahrenheit, melting the rock that lay between 9 and 15 miles below the surface. The pressure on that molten rock forced huge amounts of it into cracks and fissures of the surrounding host rock, where it formed deposits of what are known as pegmatites.
It took some 100 million years for the deeply buried molten rock to cool down and crystallize. Thanks to the depth at which it was buried and to the lack of water where all this was happening, the pegmatites formed almost without impurities. Generally speaking, the pegmatites are about 65 percent feldspar, 25 percent quartz, 8 percent mica, and the rest traces of other minerals. Meanwhile, over the course of some 300 million years, the plate under the Appalachian Mountains shifted upward. Weather eroded the exposed rock, until the hard formations of pegmatites were left near the surface.
Long before Christopher Columbus sailed from Spain, Native Americans mined the shiny, glittering mica and used it for grave decorations and as currency. The first European visitor to the area was a Spanish explorer in 1567, but he didn’t find much to interest him. American settlers began trickling into the mountains in the 1800s, scratching out a living as farmers. A few prospectors tried their hands at the mica business, but were stymied by the steep mountain geography. “They couldn’t find a way to get their stuff to market,” said David Biddix, a scruffy-haired amateur historian who has written three books about Mitchell County, where Spruce Pine sits. Biddix’s family has lived there since 1802. “There were no rivers, no roads, no trains. They had to haul the stuff out on horseback,” he said.
The region’s prospects started to improve in 1903 when the South and Western Railroad company, in the course of building a line from Kentucky to South Carolina, carved a track up into the mountains,1 a serpentine marvel that loops back and forth for twenty miles to ascend just 1,000 feet. Once this artery to the outside world was finally opened, mining started to pick up. Locals and wildcatters dug hundreds of shafts and open pits in the mountains of what became known as the Spruce Pine Mining District, a swath of land twenty-five miles by ten miles that sprawls over three counties.
At a cluttered desk in the living room of his modest house, which sits in a subdivision built on land reclaimed from a defunct mine, Biddix showed me old black-and-white photos he’s collected of the wildcat mines of the era—rough-hewn pits scores of feet deep, worked by grim-faced men in overalls wielding shovels and picks. Biddix’s grandfather was one of them. His grandmother worked in a mica sheeting house, pulling apart the rocks’ translucent, flat, page-like sheets. Mica used to be prized for wood- and coal-burning stove windows and for electrical insulation in vacuum tube electronics. It’s now used mostly as a specialty additive in cosmetics and things like caulks, sealants, and drywall joint compound. The sheeting houses are still open, but these days they import the mica from India, said Biddix.
During World War II, demand for mica and feldspar, which are found in tremendous abundance in the area’s pegmatites, boomed. Prosperity came to Spruce Pine. The town quadrupled in size in the 1940s. At its peak, Spruce Pine boasted three movie theaters, two pool halls, a bowling alley, and plenty of restaurants.2 Three passenger trains came through every day.
Toward the end of the decade, the Tennessee Valley Authority sent a team of scientists to Spruce Pine tasked with further developing the area’s mineral resources. They focused on the moneymakers, mica and feldspar.
The problem was separating those minerals from the other ones. A typical chunk of Spruce Pine pegmatite looks like a piece of strange but enticing hard candy: mostly milky white or pink feldspar, inset with shiny mica, studded with clear or smoky quartz and flecked here and there with bits of deep red garnet and other-colored minerals. For years, locals would simply dig up the pegmatites and crush them with hand tools or crude machines, separating out the feldspar and mica by hand. The quartz that was left over was considered junk, at best fit to be used as construction sand, more likely th
rown out with the other tailings.
Working with researchers at North Carolina State University’s Minerals Research Laboratory in nearby Asheville, the TVA scientists developed a much faster and more efficient method to separate out minerals, called froth flotation. “It revolutionized the industry,” said Glover. “It made it evolve from a mom-and-pop individual industry to a mega-multinational corporation industry.”
Froth flotation involves running the rock through mechanical crushers until it’s broken down into a heap of mixed-mineral granules.3 You dump that mix in a tank, add water to turn it into a milky slurry, and stir well. Next, add reagents—chemicals that bind to the mica grains and make them hydrophobic, meaning they don’t want to touch water. Now pipe a column of air bubbles through the slurry. Terrified of the water surrounding them, the mica grains will frantically grab hold of the air bubbles and be carried up to the top of the tank, forming a froth on the water’s surface. A paddle wheel skims off the froth and shunts it into another tank, where the water is drained out. Voilà: mica.
The remaining feldspar, quartz, and iron are drained from the bottom of the tank and funneled through a series of troughs into the next tank, where a similar process is performed to float out the iron. Repeat, more or less, to remove the feldspar.
It was the feldspar, which is used in glassmaking, that first attracted engineers from the Corning Glass Company to the area. At the time, the leftover quartz grains were still seen as just unwanted by-products. But the Corning engineers, always on the lookout for recruits to put to work in the glass factories, noticed the quartz’s purity and started buying it as well, hauling it north by rail to Corning’s facility in Ithaca, New York, where it was turned into everything from windows to bottles.4
One of Spruce Pine quartz’s greatest achievements in the glass world came in the 1930s, when Corning won a contract to manufacture the mirror for what was to be the world’s biggest telescope, ordered by the Palomar Observatory in Southern California. Making the 200-inch, twenty-ton mirror involved melting mountains of quartz in a giant furnace heated to 2,700 degrees Fahrenheit, writes David O. Woodbury in The Glass Giant of Palomar.5 Once the furnace was hot enough, “three crews of men, working day and night around the clock, began ramming in the sand and chemicals through a door at one end. So slowly did the ingredients melt that only four tons a day could be added. Little by little the fiery pool spread over the bottom of the furnace and rose gradually to an incandescent lake fifty feet long and fifteen wide.” The telescope was installed in the observatory in 1947. Its unprecedented power led to important discoveries about the composition of stars and the size of the universe itself. It is still in use today.
Significant as that telescope was, Spruce Pine quartz was soon to take on a far more important role as the digital age began to dawn.
In the mid-1950s, thousands of miles from North Carolina, a group of engineers in California began working on an invention that would become the foundation of the computer industry. William Shockley, a pathbreaking engineer at Bell Labs who had helped invent the transistor, had left to set up his own company in Mountain View, California, a sleepy town about an hour south of San Francisco, near where he had grown up. Stanford University was nearby, and General Electric and IBM had facilities in the area, as well as a new company called Hewlett-Packard. But the area known at the time as the Santa Clara Valley was still mostly filled with apricot, pear, and plum orchards. It would soon become much better known by a new nickname: Silicon Valley.
At the time, the transistor market was heating up fast. Texas Instruments, Motorola, and other companies were all competing to come up with smaller, more efficient transistors to use in, among other products, computers. The first American computer, dubbed ENIAC, was developed by the army during World War II; it was a hundred feet long and ten feet high, and it ran on 18,000 vacuum tubes. Transistors, which are tiny electronic switches that control the flow of electricity, offered a way to replace those tubes and make these new machines even more powerful while shrinking their tumid footprint. Semiconductors—a small class of elements, including germanium and silicon, which conduct electricity at certain temperatures while blocking it at others—looked like promising materials for making those transistors.
At Shockley’s start-up, a flock of young PhDs began each morning by firing up kilns to thousands of degrees and melting down germanium and silicon. Tom Wolfe once described the scene in Esquire magazine: “They wore white lab coats, goggles, and work gloves. When they opened the kiln doors weird streaks of orange and white light went across their faces . . . they lowered a small mechanical column into the goo so that crystals formed on the bottom of the column, and they pulled the crystal out and tried to get a grip on it with tweezers, and put it under microscopes and cut it with diamond cutters, among other things, into minute slices, wafers, chips; there were no names in electronics for these tiny forms.”
Shockley became convinced that silicon was the more promising material and shifted his focus accordingly. “Since he already had the first and most famous semiconductor research and manufacturing company, everyone who had been working with germanium stopped and switched to silicon,” writes Joel Shurkin in his biography of Shockley, Broken Genius.6 “Indeed, without his decision, we would speak of Germanium Valley.”
Shockley was a genius, but by all accounts he was also a lousy boss. Within a couple of years, several of his most talented engineers had jumped ship to start their own company, which they dubbed Fairchild Semiconductor. One of them was Robert Noyce, a laid-back but brilliant engineer, only in his mid-twenties but already famous for his expertise with transistors.
The breakthrough came in 1959, when Noyce and his colleagues figured out a way to cram several transistors onto a single fingernail-sized sliver of high-purity silicon. At almost the same time, Texas Instruments developed a similar gadget made from germanium. Noyce’s, though, was more efficient, and it soon dominated the market. NASA selected Fairchild’s microchip for use in the space program, and sales soon shot from almost nothing to $130 million per year. In 1968, Noyce left to found his own company. He called it Intel, and it soon dominated the nascent industry of programmable computer chips.
Intel’s first commercial chip, released in 1971, contained 2,250 transistors. Today’s computer chips are often packed with transistors numbering in the billions. Those tiny electronic squares and rectangles are the brains that run our computers, the Internet, and the entire digital world. Google, Amazon, Apple, Microsoft, the computer systems that underpin the work of everything from the Pentagon to your local bank—all of this and much more is based on sand, remade as silicon chips.
Making those chips is a fiendishly complicated process. They require essentially pure silicon. The slightest impurity can throw their whole tiny systems out of whack.
Finding silicon is easy. It’s one of the most abundant elements on Earth. It shows up practically everywhere bound together with oxygen to form SiO2, aka quartz. The problem is that it never occurs naturally in pure, elemental form.7 Separating out the silicon takes considerable doing.
Step one is to take high-purity silica sand, the kind used for glass.8 (Lump quartz is also sometimes used.) That quartz is then blasted in a powerful electric furnace, creating a chemical reaction that separates out much of the oxygen. That leaves you with what is called silicon metal, which is about 99 percent pure silicon. But that’s not nearly good enough for high-tech uses. Silicon for solar panels has to be 99.999999 percent pure—six 9s after the decimal. Computer chips are even more demanding. Their silicon needs to be 99.99999999999 percent pure—eleven 9s. “We are talking of one lonely atom of something that is not silicon among billions of silicon companions,” writes geologist Michael Welland in Sand: The Never-Ending Story.
Getting there requires treating the silicon metal with a series of complex chemical processes. The first round of these converts the silicon metal into two compounds. One is
silicon tetrachloride, which is the primary ingredient used to make the glass cores of optical fibers. The other is trichlorosilane, which is treated further to become polysilicon, an extremely pure form of silicon that will go on to become the key ingredient in solar cells and computer chips.
Each of these steps might be carried out by more than one company, and the price of the material rises sharply at each step. That first-step, 99 percent pure silicon metal goes for about $1 a pound9; polysilicon can cost ten times as much.10
The next step is to melt down the polysilicon. But you can’t just throw this exquisitely refined material in a cook pot. If the molten silicon comes into contact with even the tiniest amount of the wrong substance, it causes a ruinous chemical reaction. You need crucibles made from the one substance that has both the strength to withstand the heat required to melt polysilicon, and a molecular composition that won’t infect it. That substance is pure quartz.11
This is where Spruce Pine quartz comes in. It’s the world’s primary source of the raw material needed to make the fused-quartz crucibles in which computer-chip-grade polysilicon is melted. A fire in 2008 at one of the main quartz facilities in Spruce Pine for a time all but shut off the supply of high-purity quartz to the world market, sending shivers through the industry.12
Today one company dominates production of Spruce Pine quartz. Unimin, an outfit founded in 1970, has gradually bought up Spruce Pine area mines and bought out competitors, until today the company’s North Carolina quartz operations supply most of the world’s high- and ultra-high-purity quartz.13 (Unimin itself is now a division of a Belgian mining conglomerate, Sibelco.) In recent years, another company, the imaginatively titled Quartz Corp, has managed to grab a small share of the Spruce Pine market. There are a very few other places around the world producing high-purity quartz,14 and many other places where companies are looking hard for more. But Unimin controls the bulk of the trade.
