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Ivory

life science Maturity 11-13 Next article →

Ivory is a dense, white material sourced from the tusks and teeth of various mammals.

Cylindrical Ivory Casket
Cylindrical Ivory Casket

While elephant tusks are the most famous source, ivory can also come from walruses, hippopotamuses, whales, and narwhals. Chemically, ivory consists mainly of dentin, which is a structural part of teeth and tusks. This material is a biomineral composite made of collagen fibers mineralized with hydroxyapatite. This specific composition provides ivory with remarkable mechanical properties, such as high stiffness and toughness. Because it is so durable, ivory has been a highly valued material for both art and functional objects throughout human history.

The strength of ivory comes from its unique microscopic structure. The dentin is built from a network of mineralized collagen fibers. When ivory is polished, these fibers often create a visible checkerboard pattern known as the Schreger pattern. Scientists believe this pattern helps prevent crack propagation by dispersing stress throughout the material. Ivory also shows a property called anisotropy, meaning its strength changes depending on the direction. For example, the circumferential planes of a tusk can be up to 25% harder than the radial planes. This directional viscoelasticity allows the material to handle repeated wear, which is why it was once used for piano keys.

Historically, the trade of finished ivory products began in the Indus Valley. In the Harappan civilization, ivory was a major product used for trading. Archaeologists have found many Harappan ivory items, such as kohl sticks, pins, awls, and dice.

Ivory powder measure - DPLA - eaab2fc72b4fb9a1d2c4b7a5d31bffd1 (cropped)
Ivory powder measure - DPLA - eaab2fc72b4fb9a1d2c4b7a5d31bffd1 (cropped)

In ancient China, ivory moved along the Northern Silk Road as early as the first century BC. Southeast Asian kingdoms also sent Indian elephant tusks to China as part of annual tribute caravans. These items were used for everything from religious images to the stems of opium pipes.

Different cultures used ivory in very specific ways. In the Greco-Roman world, artists used ivory to create high-value works of art and religious objects. They even used small pieces of ivory to represent the white of the eyes in statues. In Southeast Asia, ivory was prized for its ability to create airtight seals in containers. Officials in countries like Myanmar and Thailand used carved ivory seals to stamp official documents. In the Philippines, the Santero culture used ivory to craft the faces and hands of Catholic icons.

Vierge a l'Enfant debout
Vierge a l'Enfant debout

During the 19th century, the ivory industry grew significantly in the United States. In the 1860s, towns like Deep River and Ivoryton in Connecticut became major centers for ivory milling. This was driven by a massive demand for ivory piano keys. At one point, up to 90 percent of all ivory imported into the U.S. was processed in Connecticut.

Decorated ivory
Decorated ivory

In Japan, the Edo period saw the rise of popular ivory carvings called netsuke. Later, during the Meiji period, the Japanese government promoted ivory crafts at World's Fairs, where they were admired by Western museums and the Imperial Family.

However, the demand for ivory has had a devastating impact on animal populations. In the first half of the 20th century, Kenyan elephant herds were devastated by the demand for piano keys. In 1930, it was estimated that acquiring 40 tons of ivory required killing approximately 700 elephants. The most dramatic decline occurred in the 1980s. During that decade, the African elephant population plummeted from 1.3 million to roughly 600,000. This massive loss was partly due to the increased demand for ivory hanko, or name seals, in Japan.

Today, the international trade of natural ivory from threatened species is strictly regulated or illegal. Organizations like CITES work to manage the trade to prevent further species decline. Because of these protections, many countries have banned the sale of elephant ivory entirely. To replace natural ivory, humans have developed synthetic substitutes. We can also use the tagua nut, which can be carved similarly to ivory. These alternatives allow us to create beautiful objects without harming endangered animals.

Ivory trade
Ivory trade
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🖼️ Images & Media (7)
File:Horn Louvre OA4069.jpg
Horn Louvre OA4069.jpg
File:Cylindrical Ivory Casket.jpg
Cylindrical Ivory Casket.jpg
File:Vierge a l'Enfant debout.jpg
Vierge a l'Enfant debout.jpg
File:Ivory tabernacle Louvre OA2587.jpg
Ivory tabernacle Louvre OA2587.jpg
File:Ivory powder measure - DPLA - eaab2fc72b4fb9a1d2c4b7a5d31bffd1 (cropped).jpg
Ivory powder measure - DPLA -...
File:Decorated ivory.JPG
Decorated ivory.JPG
File:Ivory trade.jpg
Ivory trade.jpg
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