Pottery

• 1. Introduction

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  Pottery dates back further than agriculture, further than permanent villages, all the way to the height of the most recent ice age. The Venus of Dolni Vestonice, a small statuette of a nude female figure found in the modern-day Czech Republic, was shaped from clay and dated to 29,000 to 25,000 BC. At that moment there were no farms, no cities, no writing. Yet someone gathered clay, formed a figure, and committed it to fire. How did a craft this old survive every culture that touched it? Why do archaeologists name entire vanished peoples after the broken cups they left behind? And how did a lump of soft earth become tableware, sewer pipes, electrical insulators, and laboratory ware? The answers run from a cave in China to a firing mound in Mali, from the kilns of Stoke-on-Trent to the lungs of the workers who tended them.

• 2. Earth, Fire, And Three Wares

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  ASTM International defines pottery as all fired ceramic wares that contain clay when formed, setting aside technical, structural, and refractory products. The craft splits traditionally into three types: earthenware, stoneware, and porcelain. Each can be glazed or unglazed, and each can carry decoration. The dividing line is heat. Earthenware can mature as low as 600 degrees Celsius and is normally fired below 1,200. Stoneware is fired in a kiln at roughly 1,100 to 1,200 degrees Celsius, which leaves it stronger and non-porous to liquids. Porcelain reaches between 1,200 and 1,400 degrees Celsius, the highest of the three.

  Unglazed earthenware is porous, which limits its use for storing liquids or serving food. That weakness made the invention of ceramic glaze a turning point, since a glassy coating finally made impermeable pottery possible. The toughness, strength, and translucence of porcelain come mainly from vitrification and the formation of a mineral called mullite within the body at high temperatures. The Chinese, who developed stoneware very early, never drew the same boundaries Europeans did. They group stoneware and porcelain together as high-fired wares, opposed to low-fired earthenware, which is why the question of when porcelain was first made remains tangled. Some pieces refuse the whole system: fritware uses little or no clay, so it falls outside all three groups entirely.

• 3. Reading The Sherds

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  Because pottery is so durable, fragments survive for millennia long after objects made of organic materials have decayed. At most archaeological sites the broken pieces are the most common and important artifacts to endure, which is why so many prehistoric cultures are named after their pottery. Carbon dating reveals an object's age. Trace-element analysis, mostly by neutron activation, identifies the source of the clay. The thermoluminescence test estimates the date of last firing. Scientists examining sherds from prehistory even discovered that iron materials in clay, during high-temperature firing, record the state of the Earth's magnetic field at that moment.

  Fabric analysis treats the clay body itself as evidence. The body, also called the paste or fabric, holds a clay matrix of grains smaller than 0.02 millimetres alongside larger clay inclusions visible to the naked eye. Studying the matrix, the inclusions, and the firing conditions reveals how a piece was made, how it was decorated, and how it was used. The six fabrics of Kalibangan show what this can do. Fabric analysis there identified a differentiated culture previously thought to be typical Indus Valley civilisation culture.

  Olivier P. Gosselain proposed reading pottery through the chaine operatoire of its production to map cross-cultural interaction. Early Sub-Saharan African methods fall into three categories: visible techniques like decoration and firing, techniques tied to materials such as clay selection, and techniques for moulding the clay. The visible ones are easily imitated, hinting at distant connections like shared trade. The harder skills, such as clay selection, pass only between potters in direct contact. That kind of transfer implies a shared language or pre-existing norms of contact between two groups.

• 4. From Pinch To Press

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  Hand-shaping was the earliest method, built from pinching solid balls of clay and coiling ropes of it, with parts often joined using slip. Then came the potter's wheel, whose earliest known example dates to the middle of the 5th millennium BC, from the Cucuteni-Trypillia culture in western Ukraine. The word throwing comes from the Old English thrawan, meaning to twist or turn. A potter centres a ball of clay on the wheel-head, then presses, squeezes, and pulls it upward into a hollow shape. Throwing demands skill and reproduces poorly, and it can only make wares with radial symmetry on a vertical axis.

  Industry answered with machines that traded artistry for speed. Jiggering and jolleying, used in pottery since at least the 18th century, shape one face of a piece with a tool while a rotating plaster mould shapes the other. Jiggering makes flatware like plates; jolleying makes hollowware like cups. The roller-head machine, developed in the United Kingdom just after World War II by the company Service Engineers, replaced the fixed profile with a rotary tool and can form a piece roughly every five seconds, about twelve pieces per minute. It remains the dominant method for both flatware and hollowware.

  Slip casting handles shapes other methods cannot reach. A liquid slip is poured into an absorbent plaster mould, water is drawn out, and a layer of clay clings to the internal surface before excess is poured off. It was first practised, to a limited extent, in China as early as the Tang dynasty. Pressure casting, developed in the 1970s for sanitaryware, pushes the idea further with polymeric moulds that withstand external pressures up to 4.0 megapascals, far beyond the 0.1 to 0.2 megapascals of capillary forces in plaster. Injection moulding, borrowed from thermoplastics, can produce a cup and its handle in a single process, eliminating the separate handle-fixing step.

• 5. The Long Climb To Heat

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  Reaching high temperatures was, historically, a long-lasting challenge. The earliest pots were bonfire or pit-fired, where firing times might be short but peak temperatures could climb quickly toward perhaps 900 degrees Celsius. Firing produces permanent, irreversible chemical and physical changes, and only after firing does a clay object become pottery. In lower-fired wares the change is sintering, the fusing of coarser particles at their points of contact. In porcelain, the higher heat greatly alters the physical, chemical, and mineralogical properties of the body. The combination of heat and time carries its own name: heatwork.

  The air inside a kiln shapes the result as much as the temperature. Iron oxides drive much of this. Iron(III) oxide gives brown-red colours, while iron(II) oxide gives much darker tones including black. By restricting the air supply or supplying excess fuel, a potter creates a reducing atmosphere, oxygen-deficient, where carbon monoxide pulls oxygen away from the iron and shifts the colour. Kilns can be monitored by pyrometers, thermocouples, and pyrometric devices, and the peak temperature is often held steady to soak the wares.

  Different traditions reached heat differently. In a Western adaptation of Japanese raku, wares are pulled from the kiln while still hot and smothered in ashes, paper, or woodchips, producing a carbonised look; the same technique appears in Malaysia in making labu sayong. In Mali, a firing mound replaces a brick or stone kiln. Women and girls of the village carry the unfired pots, lay sticks for a foundation, position the pots among the branches, and pile grass high to finish the mound. A senior potter lights a handful of grass, then runs around the circumference touching the burning torch to the dried grass. Some mounds are still being built as others already burn.

• 6. Glaze, Gold, And Surface

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  Salt-glazing once filled kitchens and, later, sewers. Common salt thrown into the kiln volatilises in the heat and settles on the ware, reacting with the body to form a sodium aluminosilicate glaze. It was used for domestic pottery in the 17th and 18th centuries, but the process is now largely obsolete, its last large-scale use being salt-glazed sewer pipes before clean air restrictions ended it. Ash glazing draws its flux from the ash of burned plant matter, often combustion waste from the kiln fuel itself, and it survives among a small number of studio potters who value its unpredictability. The Catawba Valley Pottery in the United States is noted among the rare non-Far-Eastern examples.

  Gold decoration marks the highest-class wares and comes in several forms. Acid Gold, developed in the early 1860s at the English factory of Mintons Ltd, etches the glazed surface with diluted hydrofluoric acid before the gold is applied. Best gold emerges from the kiln dull and must be burnished to reveal its full colour, while Bright gold needs no burnishing at all. Mussel gold, an older method, was made by rubbing together gold leaf, sugar, and salt, then washing away the solubles.

  Newer surfaces arrived through machinery. Pad printing, developed in the late 1940s, presses flexible silicone pads onto three-dimensional objects and remains the standard for high-speed branding on mass-produced tableware. Digital printing, patented in the late 1990s and commercially viable by 2005, became the tile industry standard by 2012 before reaching tableware. Using metal-oxide inks, its printers can replicate textures like marble with photorealistic precision and decorate irregular surfaces without contact. Agateware, made by partially blending clays of different colours, is called neriage in Japan and marbled ware in China, where such pieces have been made since at least the Tang dynasty.

• 7. Potter's Rot

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  In one study reported in 2022, of 106 UK pottery workers, 55 per cent had at least some stage of silicosis. The disease is an occupational lung condition caused by inhaling crystalline silica dust over many years, known colloquially among potters as potter's rot. Its danger was recognised early. Less than ten years after calcined flint was introduced in 1720 as a raw material for the British ceramics industry, its harm to workers' lungs had already been noted. Protection eventually came through legislation such as The Pottery (Health and Welfare) Special Regulations 1950 in the UK, alongside processing materials as wet suspensions or using local exhaust ventilation.

  Lead poisoning, called plumbism, shadowed the glazers. The hazard was recognised at least as early as the nineteenth century. The first UK law limiting pottery workers' exposure to lead came in the Factories Act Extension Act in 1864, with further amendments in 1899. The other recognised risks of the trade include heavy metal poisoning, poor indoor air quality, dangerous sound levels, and possible over-illumination.

  The city of Stoke-on-Trent earned the nickname The Potteries, its factories known colloquially as Pot Banks. It became one of the first industrial cities of the modern era, where as early as 1785 some 200 pottery manufacturers employed 20,000 workers, with Josiah Wedgwood, who lived from 1730 to 1795, as its dominant leader. North Staffordshire pioneered bone china, jasperware, and transfer printing. Then the work drained away. Employment fell from 45,000 in 1975 to 23,000 in 1991, and to 13,000 by 2002.

• 8. A Craft Without A Single Origin

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  Pottery may well have been discovered independently in many places, probably by accident at the bottom of fires built on clay soil. As of 2012, the earliest pottery vessels found anywhere, dated to 20,000 to 19,000 years before the present, came from Xianren Cave in the Jiangxi province of China. Other early vessels turned up in southern China's Yuchanyan Cave from 16,000 BC and in the Russian Far East's Amur River basin from 14,000 BC. In Japan, the Odai Yamamoto I site of the Jomon period yielded earthenware fragments dated as early as 14,500 BC in excavations in 1998. The word Jomon means cord-marked, describing the impressions left by pressing rope into the clay.

  Africa holds the oldest pottery outside East Asia. In 2007, Swiss archaeologists found some of it at Ounjougou in central Mali, dating to at least 9,400 BC, the same period as the East Asian finds and tied in both regions to the end of the ice age. As new grassland appeared, hunter-gatherers in Mali made pottery to store wild pearl millet and small arrowheads to hunt small game. After 8,000 BC, ceramics surged into a continent-wide phenomenon across Sub-Saharan Africa.

  Every region met clay on its own terms. Europe's oldest pottery, from around 6700 BC, was found on the banks of the Samara River in Russia's middle Volga region, attributed to the Yelshanka culture. In the Americas, the earliest dates in Brazil run from 9,500 to 5,000 years ago, and Maya potters later made finely painted beakers crowded with figures and texts. Two places never took up the craft on their own: Polynesians settling islands farther east abandoned the need for pottery as they adapted to cooking in earth ovens, and the Indigenous Australians never developed it at all. When Europeans reached Australia, English potters analysed its clay deposits as excellent, and less than twenty years after arrival they were making pottery from the very ground the first inhabitants had left unfired.