Stories in Stone

by David B. Williams

  Pliny was a lone voice of opprobrium, railing against a time-tested formula. For the Romans of the late Republic and early imperial age, marble equaled luxury, luxury signified wealth, and wealth translated into power.21 As classics scholar J. Clayton Fant has observed, marble was a particularly good symbol of wealth because it was expensive, imported, and unnecessary.

  Archaeologists usually point to Greece as the reason Romans turned to marble. Completely conquered by the second century BCE, Greece and its buildings stood as shining examples to the Romans, sort of like the big brother or sister a younger sibling wants to emulate. Beginning with the Cycladic culture over three thousand years earlier, the people of the northeastern Mediterranean had utilized marble for art, religion, and architecture. The Greeks chose white marble for their greatest buildings because of the stone’s luminosity and sparkle, proximity, and ease of cutting, at least relative to granite. When the Romans subjugated Greece, they started quarrying the Greeks’ local stone from areas such as Mount Hymettus, near Athens, and Mount Pentelicus, location of the quarries for the Parthenon’s stone.22

  Imitation may be the highest form of flattery, but working your former opponent’s quarries also signified power. We not only conquered you, we are taking your stones for our monuments and you cannot stop us. Lord Elgin and the marble panels he pilfered from the Parthenon get worse press, but the Romans liberated Greek statues two thousand years before the British. They repeated a similar takeover when Egypt fell under Augustus. The conquerors acquired vast new quarries, as well as an obelisk or ten.

  As their empire grew, so did the Romans’ desire for marble and other flashy stone. From Numidia they quarried butter yellow giallo antico. The island of Chios produced portasanta, a stone often compared to roast beef in color and texture; its name translates to “holy door,” a reference to its use as doorjambs at St. Peter’s and elsewhere. In Turkey the Romans acquired the brecciated purple, black, and white africano. A stone that resembles broken Oreo cookies, with the straightforward name bianco e nero antico, arrived from St. Girons, France. The Romans went to Egypt and took a purple igneous stone, porfido or lapis porphyrites, from which came the words porphyry and purple. Back in Greece, they raided Thessaly for verde antico, an emerald and white metamorphic stone, known as serpentine for its resemblance to snake skin. Closer to home the Romans quarried their lone indigenous polychromatic marble, cottanello, a white and brownish red, swirled stone.

  Although the Romans considered these rocks to be marble, modern geologists do not. To them, a marble is metamorphosed limestone. To the Romans, who called marble marmor—from the Greek adjective marmareos, meaning shining or shimmering—marble referred to any hard rock suitable for sculpture or architecture. Such “honorary marbles,” to borrow a term from archaeology, included granite, breccia (rocks composed of angular fragments), porphyry, and serpentine. Not that this expansive definition died out with the Romans. Go to any store selling architectural stone and you will find a plethora of non–metamorphosed limestone labeled as marble.

  Despite the abundance of colorful stone the Romans did not stop using white marble. Seeking a local source, they found it in the foothills of the Apuan Alps, about two hundred miles north of Rome. The Romans knew the stone as Lunense marble, after the town of Luna, a port on the Ligurian Sea six miles from Carrara, originally celebrated for its cheese,wood, and wine. Later heralded as Carrara marble, after the town nestled at the foot of the Apuans, the creamy white rock has been quarried for well over two thousand years.

  Good evidence, including tool marks and written sources, shows that the Romans began quarrying in the second century BCE. By the time of Augustus’s rule, from 27 BCE to 14 CE, Lunense marble had achieved its sine qua non status in public buildings. (Ever disgruntled by other people’s ostentatious tastes, Pliny criticized the first person to use solid Carrara columns in his home.) Recently, archaeologists have dug down through the layers of the ancient stone dumps, known as ravaneti, that cover the Apuans and found pieces of cut marble carbon-dated at 763 BCE.23 The Etruscans inhabited the region at the time and probably collected marble they found on the ground instead of quarrying it.

  Carrara achieved its status in part because the Emperor owned the quarries. His minions established an efficient management system, which employed a host of functionaries to supervise skilled workers and slaves, manage expenses, and market stone. Quarries operated as assembly lines, offering semifinished decorative and architectural elements, such as columns, tables, entablatures, and statue bases. Skilled craftsmen worked on specific elements, aided by men who understood the strengths and weaknesses of marble and advised how to work the stone.

  Finished products traveled from Luna by boat down the coast to the Roman port of Ostia and twenty miles up the Tiber River to an area in Rome now known as the Marmorata.24 In contrast to Michelangelo, the Romans were able to transport massive quantities of stone because they had established a widespread and well-run network to do so. Successful transport of marble benefited from its elite status: The emperor controlled the system, which supplied stone for his projects and for his wealthy friends. You can imagine that most suppliers would want to stay on the good side of the emperor.

  As the closest source of high-quality white marble to Rome, Carrara dominated the market for the next two centuries, when politics and the silting in and closing down of Luna’s harbor raised the prominence of eastern marbles. But for those two-hundred-plus years including and following Augustus’s reign, Carrara gave Roman buildings their face. Wander the Forum in Rome and you cannot help but notice the gleaming columns, the arches of Constantine, Septimus Severus, and Titus, or the elegant Trajan’s Column. Wherever Romans wanted to show off their wealth they built with Carrara marble. Most marble, though, except for columns and capitals, served little structural purpose in buildings, whether grand or more utilitarian. Instead, inexpensive materials, such as brick and concrete, provided the structure and thin slabs of marble provided the look of luxury. Augustus’s famed boast of finding Rome a city of brick and leaving it a city of marble was a veiled reference to this use of Carrara.

  With the fall of the Roman Empire in 476, Rome settled into decay that lasted for a thousand years. A few popes tried to reinvigorate the Eternal City, but limited monumental building occurred. When Pope Martin V arrived in Rome in 1420 he found it so “dilapidated and deserted that it bore hardly any resemblance to a city.”25 Martin started a building and renovation spree that led to new roads, new churches, and a grand hospital. By the time Michelangelo first visited Rome, in 1496, the city had become a center of construction.

  Walking around the revitalized Rome, like architects and artists past and present, Michelangelo would have encountered the ruins from the great buildings of the Roman Empire. They, too, would become his teachers. The ancient structures taught him about the vocabulary and motifs of architecture. Their scale inspired him and gave him the ambition to attempt a feat not tried since the glory days of the empire, to work with columns made from a single stone, as opposed to the common practice of building columns with drums of stone. Although he rarely followed the classical style precisely, Michelangelo “invariably retained essential features from ancient models in order to force the observer to recollect the source,” as James Ackerman wrote in his classic The Architecture of Michelangelo.26

  In Rome, Michelangelo would also have seen scores of Greek and early Roman sculptures. Modern art historians have argued that sculptures such as the Torso Belvedere, Lion Attacking a Horse, and the Cesi Juno, the latter of which Michelangelo called “the most beautiful object in all Rome,” influenced, motivated, and stimulated him.27 They challenged his understanding of marble and showed him the stone’s possibilities.

  He further learned about materials and quality from the great buildings in Rome. He saw the marble, how the Romans splurged by using solid blocks of it in their finest buildings, and how marble bestowed stature and elegance. Rome gave Michelangelo “a spark for ex
plosions of fancy,” wrote Ackerman, explosions that helped seal his reputation and that of marble, especially of Carrara marble.28

  I first saw Carrara and its quarries from a car window, while driving north out of Pisa. Marjorie and two friends, John and Terry, and I were about twenty-five miles or so from the green foothills of the Apuan Alps. Broken clouds created a pattern of shade and light punctuated by bright white splotches, which several guidebooks explained: “No, that isn’t snow, it’s marble.” After an initial giddiness at seeing the Carrara, however, my excitement began to fizzle. Where were the charming old buildings? Quarries had been worked in these mountains more or less continuously for the past five centuries and I expected quaint structures made of the local stone. Instead, the road felt like many other industrial/shopping mall districts I had driven by, with billboards, stores selling marble gewgaws, and warehouses creating a monotonous blur of banality. The stone mills—each with stacks of marble blocks, pallets of sliced stone slabs, and massive cranes for ferrying the stone—had a certain charm, but they looked like any stone mill you can see in Indiana.

  Closer to the mountains the wide, industrial street gave way to a confusing maze of narrow, often one-way, poorly marked roads. After circling around, getting lost, backtracking, and hoping we knew where we were, we crammed our little rental car into a spot along a lane about twice as wide as our car. A typical Carrarese building, a four-story, stucco-covered structure, stood about two feet from the car door. On the other side of the road, and twenty feet below us in a concrete-sided trench, ran the Torrente Carrione, Carrara’s couple-of-inches-deep trickle of a stream.

  Abandoning the car, the four of us wandered toward where we thought our bed and breakfast might be. The streets closed tighter, the sharply rising buildings turning them into canyons. Eventually they became too narrow for cars. The windows of many of the buildings were festooned with drying laundry and hanging planters. At our B&B, no one answered, so we walked into the town center, crossing a plaza with white marble paving stones, each about the size of a brick. Marble sidewalks and curbs lined most streets. Not every building was made from marble, but we had clearly entered a hub of the marble universe. Not that the locals respected their great stone; graffiti covered many marble walls and several marble statues.

  I like to think that these same narrow streets had greeted Michelangelo when he reached Carrara 510 years earlier on his expedition to find stone for the Pietà. When we finally got into our B&B, the owner told us that Michelangelo had worked in this very building and had carved the marble on the first-floor landing. The owner was a very nice person and I am sure she thought she was telling the truth. Perhaps Michelangelo had carved it to pay for lodging;money often was in short supply for him in his younger days.

  The next morning, John and I met with Paolo Conti, a geologist from the Center for Geotechnology at the University of Siena. Conti had graciously offered to take us up into the mountains to learn more about the quarries and the geology. We got in his car and drove three miles or so into the Apuans and parked in a lot next to the Ponti di Vara, a stately, five-arched, brick-and-marble bridge. Originally a route for the railroad that crisscrossed the quarries, the Ponti di Vara is barely wide enough for the hundreds of trucks that zip across it each day.

  From the parking lot, the quarries glowed a blinding white in the sunlight as they crept halfway up Mount Maggiore, which rose three thousand feet above us. Across the road yellow signs pointed to several quarries, including the Roman-era Fantiscritti, supposedly the source for the marble doorposts of the Pantheon. Another sign read VISITA LA CAVA IN GALLERIA PIU’ BELLA DEL MONDO, Visit the Most Beautiful Underground Quarry in the World.

  Pulling out several wonderful and colorful geology maps, Conti showed us that we were at the base of the Miseglia valley, one of three quarry valleys around Carrara. To the north lay Torano and to the south Colon-nata. Each cut back into the Apuans for several miles and each had quarries first opened originally by the Romans. No one knows how many quarries have pierced these mountains, but one estimate runs as high as 650. Conti’s geologic maps from 2000 listed 187 quarries.

  “We are standing here at the edge of this tectonic window of marble, surrounded by sediments,” said Conti, as he pointed to an oval of blue and purple on a geologic map of Tuscany that he had spread on his car. Blue and purple indicated metamorphosed rocks, mostly marbles but also some schists. Butter and pumpkin colors showed limestones, sandstones, and shales. The Apuan Alps were the largest zone of blue—representing an area about ten miles wide by eighteen miles long—on the entire map.

  The Carrara began life as one of those limestones 200 million years ago, about the same time the brownstones began to form. North America and Africa had begun to split apart from each other, opening the chasm that would grow into the Atlantic Ocean. Across the globe, another ocean, called Tethys, had begun to spread onto a shallow platform off the coast of what we now call Italy.

  This young sea was calm, clear, and warm. A smattering of islands popped out of the water. Along the shore, tidal flats and lagoons shifted back and forth, depending upon sea level. Sandbars made of oolitic grains formed seaward of the lagoons and a fine-grained mud of calcite accumulated on the seafloor. The few animals that did live in the sea included ammonites, foraminiferas, and bivalves.29 The Salem Limestone formed in a similar environment, only on a much larger scale and in a sea far richer in animal life.

  The shallow sea remained for several million years until an arm of the newly forming Atlantic Ocean invaded. The new waters dropped the temperature and lowered the salinity, precipitating an environmental crisis that halted calcite production. Enough calcite, however, had accumulated in the Italian sea’s short life to later lithify into an eight-hundred-to eleven-hundred-foot-thick sheet of limestone.30

  Little of consequence happened to these limestones until 27 million years ago, said Conti, when a small tectonic block, called the Corsica-Sardinian Microplate, rammed into the Italian peninsula. Corsica-Sardinia carried ocean-derived basalts, gabbros, and sediments and plowed them in a southwest–northeast direction atop the 200-million-year-old Italian limestone. For 10 to 15 million years, the persistent little plate rammed its larger neighbor, slowly piling and stacking the oceanic rocks atop the limestone.31 Under four to six miles of rock, the temperature in the limestone reached to 300 to 450 degrees Celsius and converted the limestone to marble.

  During this process of heating and squeezing, the texture of the original calcite changed as the mineral grains became more stable and more tightly packed. Crystals interlocked with neighboring crystals because the compressive forces eliminated excess pore spaces. Recrystallization often creates large crystals of calcite, which allow light to infiltrate deeply into the stone. In addition, because calcite crystals have regular cleavage planes, light bounces off these weak layers and the stone glimmers like a jewel.

  The limestone further changed on a macroscale, as it metamorphosed into marble. Ten million years of collision deformed the once horizontal limestone beds into a humped mound of folded rocks, which became more humped and more tightly folded over time. The mound, however, couldn’t sustain the squeeze and like a failed soufflé became too steep, collapsed, and spread. At the same time, the Corsica-Sardinia Plate stopped colliding and began to retreat, leaving behind marble buried under a mountain range as high as the Rockies.

  As Corsica-Sardinia started to pull away from Italy, it stretched and thinned the ground surface, like when you pull on either end of a piece of gum. Conti explained that the surface rocks responded initially by rising to form a dome and then by breaking into a series of parallel basins and ranges, one range of which we call the Apuan Alps. Later erosion removed the overlying material and revealed the Carrara marble, now exposed at the surface as a complicated mess of folded, fractured, stretched, and squeezed rock.

  Not all marble forms from burial of limestone. The Yule marble, the stone of the Lincoln Memorial and the Tomb of the Unknowns, fo
rmed when granitic magma intruded into a body of limestone and baked it. Contact metamorphism generally happens very rapidly, on the order of one hundred to a thousand years, and on a much smaller scale. At the Yule quarry, in Marble, Colorado, you can walk directly across the contact from the granite to the marble, which runs on the surface for about two miles. In contrast, a regionally metamorphosed marble, such as Carrara, can cover tens or hundreds of square miles, one reason people have valued it for two thousand years.

  To see more of the quarries, Conti suggested we head up above the next valley north,Torano. After driving for ten minutes or so, he swerved the car across the road on a hairpin turn and pulled off onto a very soft shoulder. His driving seemed like a typical geologist’s, veering abruptly to see rocks, combined with an Italian’s sanguinity at cutting across a blind turn.

  “I often bring students here,” he said, perhaps explaining his driving calm. “It’s one of the better spots to see the thick beds of limestone that became the Carrara.” We got out, I looked both ways, and we crossed the road to see the source rocks for the Carrara marble. Oaks and beeches, some of which had begun to change color, grew out of the gray, massive rock. I had encountered limestone like this before in many places. I called it “tearpants” limestone, in reference to its sharp, resistant edges. “We haven’t found many fossils in this rock but this is one place we have,” said Conti. I looked but found nothing other than a few snails crawling across the broken edges of the lackluster, 200-million-year-old limestone.

  Looking down into the Torano basin, Carrara, Italy.

  Up and up we drove as the road climbed and wound steadily through the foothills. We passed through zones of pines and under a canopy of rust-colored beeches before stopping near a small lodge, where we hoped to find lunch. Since it was closed we walked across the road and hiked up a trail to the Refugio Carrara, one of the well-stocked huts that offer food and lodging throughout the Italian Alps. We did find lunch there and I got to accomplish one of my goals for the trip.