Ivory. Ivory is a hard, white material from the tusks and teeth of animals, that consists mainly of dentine, one of the physical structures of teeth and tusks.
   The chemical structure of the teeth and tusks of mammals is the same, regardless of the species of origin, but ivory contains structures of mineralised collagen. 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 are large enough to be carved or scrimshawed.
   Besides natural ivory, ivory can also be produced synthetically, hence not requiring the retrieval of the material from animals. Tagua nuts can also be carved like ivory.
   The trade of finished goods of ivory products has its origins in the Indus Valley. Ivory is a main product that is seen in abundance and was used for trading in Harappan civilization.
   Finished ivory products that were seen in Harappan sites include kohl sticks, pins, awls, hooks, toggles, combs, game pieces, dice, inlay and other personal ornaments. Ivory has been valued since ancient times in art or manufacturing for making a range of items from ivory carvings to false teeth, piano keys, fans, and dominoes. Elephant ivory is the most important source, but ivory from mammoth, walrus, hippopotamus, sperm whale, orca, narwhal and warthog are used as well. Elk

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