Ivory

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Image:Ivory decoration.jpg
An elaborately carved ivory decoration

Ivory is a hard, white, opaque substance that is the bulk of the teeth and tusks of animals such as the elephant, hippopotamus, walrus, mammoth, narwhal, etc. Prior to the introduction of plastics, it was used for billiard balls, piano keys, bagpipes, buttons and ornamental items. The word "ivory" was traditionally applied to the tusks of elephants; in fact, the word is ultimately from Ancient Egyptian âb, âbu "elephant". Plastics have been viewed by piano purists as an inferior ivory substitute on piano keys, although other recently developed materials more closely resemble the feel of real ivory.

Contents

[edit] Structure

The chemical structure of the teeth and tusks of mammals is the same regardless of the species of origin, and the trade in certain teeth and tusks other than elephant is well established and widespread. Therefore, "ivory" can correctly be used to describe any mammalian teeth or tusks of commercial interest which is large enough to be carved or scrimshawed.

[edit] Teeth and tusks

Image:Walruses with Tusks.jpg
Pacific Walrus at Cape Peirce
Image:Mammoth ivory hg.jpg
Section through the ivory tooth of a mammoth

Teeth and tusks have the same origins. Teeth are specialized structures adapted for food mastication. Tusks, which are extremely large teeth projecting beyond the lips, have evolved from teeth and give certain species an evolutionary advantage. The teeth of most mammals consists of a root and the tusk proper.

Teeth and tusks have the same physical structures: pulp cavity, dentine, cementum and enamel. The innermost area is the pulp cavity. The pulp cavity is an empty space within the tooth that conforms to the shape of the pulp.

Odontoblasts line the pulp cavity and are responsible for the production of dentine. Dentine, which is the main component of carved ivory objects, forms a layer of consistent thickness around the pulp cavity and comprises the bulk of the tooth and tusk. Dentine is a mineralized connective tissue with an organic matrix of collagenous proteins. The inorganic component of dentine consists of dahllite. Dentine contains a microscopic structure called dentinal tubules which are micro-canals that radiate outward through the dentine from the pulp cavity to the exterior cementum border. These canals have different configurations in different ivories and their diameter ranges between 0.8 and 2.2 micrometres. Their length is dictated by the radius of the tusk. The three dimensional configuration of the dentinal tubules is under genetic control and is therefore a characteristic unique to the order.

[edit] Ivory art in the ancient world

Paleolithic Cro-Magnon man, during the late stages of the ice age, were the first to carve in ivory (mammoth tusks). Both the Greek and Roman civilizations used large quantities of ivory to make high value works of art, precious religious objects, and decorative boxes for costly objects. Ivory was often used to form the whites of the eyes of statues. The Syrian and North African elephant populations were reduced to extinction, probably due to the demand for ivory in the Classical world.

Image:Porphyrogenetus.jpg
Ivory has been a most prestigious material for carving.

Tooth and tusk ivory can be carved into an almost infinite variety of shapes and objects. A small example of modern carved ivory objects are small statuary, netsukes, jewelry, flatware handles, furniture inlays, and piano keys. Additionally, warthog tusks, and teeth from sperm whales, orcas and hippos can also be scrimshawed or superficially carved, thus retaining their morphologically recognizable shapes.

[edit] Availability

Due to the rapid decline in the populations of the animals that produce it, the importation and sale of ivory in many countries is banned or severely restricted. Much of the decline in population is due to poachers during and before the 1980s. Since the worldwide ivory trade ban in 1989 there have been ups and downs in elephant populations, and ivory trade as bans have been placed and lifted. Many African countries including Zimbabwe, Namibia and Botswana claim that ivory trade is necessary—both to stimulate their economies and reduce elephant populations which are allegedly harming the environment. A 1999 study done by Oxford University found that less than one percent of the five-hundred million US dollars ivory sales generated ever reach Africans; most of it goes to middlemen and vendors. However, in 2002 the United Nations partially lifted the ban on ivory trade, allowing a few countries to export certain amounts of ivory. The effectiveness of the policy is in question, in light of the study preceding the ban, and an updated study would be needed to evaluate the current state of the ivory trade.

Kenya, which saw its elephant populations plummet in the decade preceding the 1989 ban, claims that legalizing ivory trade anywhere in Africa will endanger elephants everywhere in Africa as poachers would attempt to launder their illegal ivory with legal stockpiles.

The 2006 Zakouma elephant slaughter in Chad is one of a long series of massacres which have eliminated 97 percent of the original 300,000 African elephant population of Chad in only four decades.

The demand for ivory is primarily from the Japanese hanko industry. Hankos are small seals. Traditionally, these hankos were also made from other material. Ivory hankos were introduced only in the last century.

Trade in the ivory from the tusks of dead mammoths has occurred for 300 years and continues to be legal. Mammoth ivory is used today to make handcrafted knives and similar implements.

A species of hard nut is gaining popularity as a replacement for ivory, although its size limits its usability. It is sometimes called vegetable ivory, or tagua, and is the seed endosperm of the ivory nut palm commonly found in coastal rainforests of Ecuador , Peru and Colombia. [1]

[edit] Types of ivory

So-called hornbill ivory, derived from a bird, is not true ivory but resembles it in some ways.

[edit] See also

[edit] External links

Wikimedia Commons has media related to:
af:Ivoor

ca:Vori da:Elfenben de:Elfenbein es:Marfil eo:Eburo fr:Ivoire hr:Bjelokost it:Avorio he:שנהב lt:Dramblio kaulas hu:Elefántcsont nl:Ivoor ja:象牙 no:Elfenben nrm:Iviéthe pl:Kość słoniowa pt:Marfim ru:Слоновая кость simple:Ivory sh:Slonovača fi:Norsunluu sv:Elfenben zh:象牙

Ivory

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