Technically, all animals with teeth have ivory, which is composed of a creamy white substance called dentin that makes up the bulk of teeth. However, some animals have particularly large teeth or tusks that lend themselves to harvesting, such as elephants, hippopotami, and whales. Ivory from these animals has been used for centuries in decorative art, and in the manufacture of objects such as pianos and billiard balls. Concerns about declining populations of elephants in particular have led to restrictions on the global trade, and many craftspeople are starting to seek out alternatives such as high quality plastics or tagua, also known as vegetable ivory.
The term has been used in English for almost 1,000 years, and originates from several African words meaning “elephant.” This suggests that elephants have been the primary source throughout European history, and given the formerly large populations of elephants in Asia as well, it is probable that India, Japan, and China also got their ivory from elephants. In North America, scrimshaw artisans got their material from walruses and whales.
Ivory is ideal for decorative art because it is hard, close grained, and takes to carving and dyes well. Sources can be shaved to make inlays or carved whole into elaborate sculptures and art pieces, as well as practical goods. It has been used in traditional art in numerous cultures, and thanks to its durability, many specimens survive, providing clues into the art and culture of other civilizations.
This material should not be confused with bone, which is an aggregate of mineralized connective tissue as well. Unlike bone, ivory does not have blood vessels, and therefore is not nearly as porous. Dentin, the material it is made of, consists of the area of the tooth above the tooth pulp and under the enamel. It contains a mixture of minerals, collagen, and water. The mineralized tissue is much stronger and more durable than bone.
Generally, ivory is divided into two basic classes: live, from recently killed animals, and dead, which has been stored. Dead ivory tends to be less durable and more subject to fracture, which means that it is not prized as much as live. Restrictions on the global trade have led to a decrease in the availability of live ivory, however, so artisans who work with this material have been forced to adapt or switch to a non-animal source, such as tagua. Tagua is the seed of the ivory palm, and is a renewable and ethical alternative.