Set in Stone


Earth, as a substance, is a highly dynamic composition of things that live, things that have lived, and the inanimate. Its make-up, both macroscopically and microscopically, is influenced by geography, the seasons, and the living things surrounding it. As the dirt and stone beneath our feet, earth plays a fundamental role, if not a passive one, in many of our day to day activities. However, earth is more than just a bystander—it is also a medium for expression, both by Mother Nature and at the hands of human beings. Capturing the shape of an object in stone, as well as observing the shapes inherent to stones, are pursuits that date back to ancient times.

As many of us learned in geography class, rocks can be classified into three main categories, depending largely on the way they were formed:

 

IGNEOUS

‘FORMED BY FIRE’

SUBJECTED TO PERIODS OF MELTING DEEP BELOW THE EARTH’S CRUST, FOLLOWED BY MOMENTS OF COOLING AND SOLIDIFICATION, THE PROPERTIES OF IGNEOUS ROCKS DEPEND ON THE RATE AT WHICH THEY COOL WHEN THEY ARE FORCED TO THE SURFACE. A RAPID SHOCK YIELDS A FINELY TEXTURED SURFACE, WHEREAS A SLOWER DROP IN TEMPERATURE LEADS TO THE AGGREGATION OF COARSE GLOBULES DISTRIBUTED THROUGHOUT.

SEDIMENTARY

‘FORMED BY THE ACTION OF WATER’

WHEN A ROCK IS CONSTANTLY EXPOSED TO THE CHEMICAL AND PHYSICAL FORCES OF WAVES, RAIN, OR ACID, PARTICLES ARE STRIPPED OFF AND CARRIED AWAY. EVENTUALLY, THEY ARE DEPOSITED ON ANOTHER SURFACE, FORMING SUBTLE LAYERS LIKE FOLD UPON FOLD OF COUNTLESS COLORED GARMENTS, SHED BY ONE AND PUT ON BY ANOTHER.

METAMORPHIC

‘FORMED BY RAPID CHANGE’

MANY NATURAL FORCES ARE AT WORK ON A ROCK AT ANY GIVEN TIME, YIELDING A PARTICULAR SET OF CONSTRAINTS DICTATED BY HEAT AND PRESSURE THAT SHAPE THE CHEMICAL COMPOSITION OF A ROCK. SOMETIMES, A SUDDEN SHIFT IN PRESSURE OR HEAT PERTURBS THAT EQUILIBRIUM, AND THE MINERALS AND MATERIALS UNDERGO AN EVENT IN WHICH THEIR ATOMS ALIGN IN PERFECT ORDER, AN EVENT KNOWN AS CRYSTALLIZATION.

However, not all earth is as hard and unyielding as granite or flint. Some are malleable, or plastic, such as the muddy clay that sucks at your boots and squelches with every footstep. Due to their high water content, clays often need to be exposed to very high heat to dry and harden. Depending on their composition, extremely high temperatures can cause the particles in clay to fuse or vitrify, creating solid surfaces that are quite suddenly impervious to the water they once contained.

A road through Monument Valley

The use of heat, pressure, and impact to shape the surface of rocks and clay have been imitated by human beings for many, many years. Sometimes, the resulting object is purely functional: a terracotta bowl, a raku cup, a stoneware teapot. Other times, the piece is almost completely aesthetic in intent: a marble statue, an alabaster carving, a sandstone relief. However, each bears a trace of the maker’s hands and tools, and an occasional few are no less impressive than the towering mountain ranges and plunging plateaus that have been carved by the unrelenting elements.

A view up a steep butte.

SCULPTURE

Sculpture utilizes two primary approaches to create a recognizable image. One, modeling, involves the ‘building up’ of an object using a plastic earth, like clay, which is shaped by the pressure of one’s fingertips into the curves and angles of the item being imitated. Layers and coils of clay are added on top of the form to slowly grow the piece, until a lump transforms into an object with limbs and appendages.

The other technique, carving, is quite the opposite; rather than adding material, flakes and chunks are whittled, scraped, and scratched away from a flat surface, revealing the form as if it were something that had been trapped within the rock itself. In this case, the medium can be quite hard, ranging from more yielding sandstone to highly resistant granite. Carving results in a series of raised and incised surfaces often referred to as relief. A flat relief contains little depth, with the highest and lowest surfaces being nearly level. An inscription on a tablet is one such example, requiring a minimal amount of exertion by the carver to make the words visible in the presence of light and shadow. On the other hand, a high relief is characterized by receding backdrops and emerging figures that seem to grow from the work itself, as if frozen during their materialization from the rock’s core. At its peak, a high relief becomes what is referred to as a full round, and the figure or form breaks away from a background and becomes free standing, as in a statue.

Puddles on the valley floor at Monument Valley

POTTERY

The use of clay also extends to pottery. In its minimal form, pot-making is as simple as flattening a ball of clay and patiently pinching it until the smooth, even, curving walls of a bowl emerge. With the use of a potter’s wheel, the symmetry of a pot emerges from the constant spin of the clay sitting on the wheel head, coaxed up into shape by the pressure of wet fingers. When throwing a pot on the wheel, an important characteristic of the clay is its plasticity. A short clay is not so malleable and may crack when shaped into a curve or a bulge, and the addition of stuffs like soda or potassium salts can improve the texture to make it more optimal for handling. The recipe for a clay, whether in sculpture or pottery, depends in part on from where it was sourced, and in part on the materials added and mixed to match personal preference for the final color and texture.

A clay bowl, of course, is wet and malleable, and cannot hold its form if held or handled. A low temperature kiln firing completely dries out the piece, and in the absence of water, it becomes a lighter, paler object. A second firing, achieved at temperatures higher than 1000 degrees centigrade, causes the particles to melt and fuse into the recognizable heft of stoneware. The sequential firing is crucial, because if the temperature rises too high before all of the water has evaporated from the walls of the vessel, the water vapor becomes trapped in pockets of the fusing stone that can lead to cracks, and at worse, an explosion.

Traditional decoration of pots relies on glazes, which get their color not from bright pigments but from the addition of finely ground metals like copper, cobalt, and iron. Before firing, a glaze is usually a dull white, or gray, or light pink. The transformation into the rich greens, resonant blues, and rusty reds we see rely on the chemical reactions that take place during firing, influenced by both temperature and oxygen level in the kiln. Glazes can be imagined as coming to life in the presence of these licking flames: glazes are fluid, crawling and creeping and shivering depending on the surface of the clay to which they try to adhere. Sometimes, the presence of different materials in the glaze of a neighboring vessel causes a pot to blush magenta instead of blue, or turn black instead of white, as if they had been conspiring while huddled inside the kiln. These incidental events, although unintended by the potter, often lend a dash of unique personality to the finished product.

A view of Monument Valley from above.

SCHOLARS’ ROCKS

Perhaps one of the strongest expressions of admiration for the natural textures and forms of rocks lies in the creation and collection of scholars’ rocks. Particularly popular during the Tang and Song dynasties in China, such rocks were often characterized by grooves, dips, and gouges resulting from wind, ice, and rain, which were further enhanced or embellished by the action of manmade tools. Sometimes, scholars’ rocks were actual rocks, displayed on pedestals and stages that lent a sense of gravity and solemnity to what could otherwise be considered a commonplace, pervasive object. Other times, depicted in ink brush paintings, carved out of wood, or more contemporaneously, modeled and covered in sheets of aluminum, scholars’ rocks were celebrations of the unpredictable and dynamic processes that nature can exhibit on an object. These items were prized for their contours, sometimes resembling an animal or a tree, or for their exterior textures, pockmarked and patterned in such a way as to be aesthetically pleasing to the collector.

The perennial attraction humans feel for the earth is still evident today, through our visits to the most remote mountain tops in the Himalayas, the cavernous walls of the Grand Canyon, and the unforgivingly harsh floor of Death Valley. Their patterns and colors draw our eyes, and their textures invite us to reach forward and feel their surfaces with our fingertips. Stones may be all around us, but their variety and beauty teach us to appreciate the forces that have shaped them into their current, transient forms.

A panoramic view of Monument Valley during sunrise.

Information on igneous, sedimentary, and metamorphic rock properties and the process of sculpture were obtained from Jack C. Rich’s The Materials & Methods of Sculpture, published in 1966 by Oxford University Press, New York, New York.

Information on clay, glazes, and pottery were obtained from Bernard Leach’s guide, A Potter’s Book, published in 1962 by Faber and Faber Limited, London.

Information on scholars’ rocks were obtained through The Metropolitan Museum of Art, New York, as described for their 2000 exhibition The World of Scholars’ Rocks: Gardens, Studios, and Paintings.

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