Ivory

• 1. Introduction

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  Ivory is a hard, white material that has tempted carvers, kings, and smugglers for thousands of years, and it comes from inside the mouths of animals. It is drawn from the tusks and teeth of mammals, and at its core it is mostly dentin, one of the physical structures of teeth and tusks. The chemical structure of teeth and tusks is the same across mammal species, yet a single material has shaped seals, swords, piano keys, and the fate of entire elephant herds. The word itself traces back to the ancient Egyptian ab, abu, meaning elephant, carried into Latin as ebor or ebur. So how did a substance grown by elephants, walruses, and whales become a global object of beauty and of slaughter? And what happens to a material so prized that acquiring it can empty a continent of its largest land animals?

• 2. What Ivory Is

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  Dentin is the heart of the matter, the biomineral that defines ivory and links it across wildly different creatures. Elephant tusks are the animal's incisors, so ivory's composition closely matches teeth in many other mammals. It is built from collagen fibers mineralized with hydroxyapatite, and natural ivory contains structures of mineralised collagen. Because the chemistry holds steady regardless of species, the word ivory can correctly describe any mammalian teeth or tusks large enough to be carved or scrimshawed. Elephant ivory is the most important source, but the material also comes from mammoth, walrus, hippopotamus, sperm whale, orca, narwhal, and warthog. Even the elk carries two ivory teeth, believed to be the remnants of tusks from their ancestors. That shared biology means a carver in one tradition and a poacher in another are, at the molecular level, working with the same thing.

• 3. Carved Across Civilizations

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  The trade in finished ivory goods has its origins in the Indus Valley, where the material appears in abundance in the Harappan civilization. Excavated Harappan sites yield kohl sticks, pins, awls, hooks, toggles, combs, game pieces, dice, inlay, and other personal ornaments. Greek and Roman workshops carved ivory into high-value works of art, religious objects, and decorative boxes, and often used it to form the white of the eyes of statues. Solinus, a Roman writer in the 3rd century, claimed that the Celtic peoples in Ireland decorated their sword-hilts with the teeth of beasts that swim in the sea. Adomnan of Iona told a story of St Columba giving a sword decorated with carved ivory as a gift, one a penitent would bring to his master to redeem himself from slavery. The Chinese long valued ivory for both art and utilitarian objects, carving everything from images of deities to the stems and end pieces of opium pipes. After the explorer Zhang Qian ventured west to form alliances, ivory moved along the Northern Silk Road for western nations as early as the first century BC, while Southeast Asian kingdoms sent Indian elephant tusks in their annual tribute caravans to China.

• 4. Seals, Daggers, And Saints

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  In Japan, ivory carvings became popular in the 17th century during the Edo period, when artisans made netsuke and kiseru carved with animals and legendary creatures, and inro inlaid with ivory. From the mid-1800s, the new Meiji government promoted and exported arts and crafts, sending elaborate ivory work to World's fairs where the best pieces were bought by Western museums, wealthy collectors, and the Japanese Imperial Family. The Buddhist cultures of Myanmar, Thailand, Laos, and Cambodia harvested ivory from their domesticated elephants, prizing it for containers because it could keep an airtight seal. Officials carved ivory into elaborate seals used to sign documents and decrees by stamping them with a unique official mark. Among Muslim Malay peoples in Malaysia, Indonesia, and the Philippines, ivory was the material of choice for the handles of kris daggers. In the Philippines, it was also used to craft the faces and hands of Catholic icons and images of saints in the Santero culture.

• 5. The Industrial Appetite

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  Up to 90 percent of the ivory imported into the United States was at one time processed in Connecticut, where Deep River and Ivoryton became centers of ivory milling in the 1860s. The demand driving those mills was the piano key, the bright white covering that defined the instrument. Before plastics, ivory also made cutlery handles, billiard balls, Scottish bagpipes, buttons, and a wide range of ornamental items. The cost of that appetite was paid in animals. To acquire 40 tons of ivory in 1930 required killing approximately 700 elephants, and in the first half of the 20th century Kenyan elephant herds were devastated by the demand for piano keys. Hippos were also preyed upon for their very hard white ivory, prized for making artificial teeth. During the Art Deco era from 1912 to 1940, dozens if not hundreds of European artists used ivory in chryselephantine statues, among them Ferdinand Preiss and Claire Colinet. Synthetic substitutes began appearing after 1800, the billiard industry challenged inventors to find a manufacturable alternative, and the piano industry finally abandoned ivory as a key covering in the 1970s.

• 6. The Mechanics Of A Tusk

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  Ivory measures 35 on the Vickers hardness scale, exceeding that of bone, a number that explains why it survived so long in objects facing repeated wear. Its flexural modulus is 14 GPa, its flexural strength 378 MPa, and its fracture toughness 2.05 MPam1/2, values that let it outperform common alternatives such as celluloid plastic and polyethylene terephthalate. The polished surface reveals a checkerboard-like Schreger pattern, long used as an attribute in ivory identification. That pattern may do more than catch the eye, it could point to a micropattern designed to prevent crack propagation by dispersing stress. The microstructure also gives ivory a strong anisotropy, meaning its strength depends on direction. Hardness measurements on three orthogonal tusk directions found that circumferential planes were up to 25 percent harder than radial planes of the same specimen. Circumferential planes showed inelastic and elastic recovery while radial planes deformed plastically, implying that ivory has directional viscoelasticity tied to collagen fibers oriented along the tusk's circumference.

• 7. Collapse And The Trade Ban

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  In the 1980s the African elephant population fell from 1.3 million to around 600,000 in ten years, a decline partly driven by solid ivory hanko, the name seals that wealth in Japan turned from wood to ivory. Machinery could carve a hanko in a matter of seconds, multiplying demand. In 1989 CITES decided to ban international trade in African elephant ivory, and the African elephant was placed on Appendix I in January 1990. The Asian elephant had been placed on Appendix I back in 1975. Investigators from the Environmental Investigation Agency found that CITES sales of stockpiles from Singapore and Burundi, 270 tonnes and 89.5 tonnes respectively, had raised the value of ivory and rewarded smugglers. Even after the ban, controlled sales continued. CITES allowed 49 tonnes from Zimbabwe, Namibia, and Botswana to go to Japan in 1997, and a 2008 sale of 108 tonnes from those three countries and South Africa went to Japan and China. Including China as an approved importer drew enormous controversy, and the price of ivory in China afterward skyrocketed, with some suspecting deliberate price fixing.

• 8. Crushers And Alternatives

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  In June 2015, more than a ton of confiscated ivory was crushed in New York City's Times Square by the Wildlife Conservation Society, sent up a conveyor belt into a rock crusher to signal that illegal trade would not be tolerated. The same society has noted that the global ivory trade leads to the slaughter of up to 35,000 elephants a year in Africa. Pressure mounted from many directions. In 2007 eBay banned international sales of elephant-ivory products under pressure from the International Fund for Animal Welfare, then disallowed any ivory sales in October 2008. China, once the biggest market for poached ivory, announced in May 2015 it would phase out legal domestic manufacture and sale, and that September China and the United States announced a nearly complete ban on the import and export of ivory. A 2019 peer-reviewed study found African elephant poaching in decline, its annual mortality rate peaking above 10 percent in 2011 and falling below 4 percent by 2017, with poaching rates strongly correlated to Chinese ivory demand and to corruption and poverty. Meanwhile, legal substitutes endure, including fossil mammoth tusks frozen in the tundra, traded for 300 years, and tagua, the vegetable ivory seed of the ivory nut palm found in the coastal rainforests of Ecuador, Peru, and Colombia.