What is the chemical composition of ivory?

Ivory tusks and teeth consist of an inner pulp cavity surrounded by dentine – a combination of connective tissues that have minerals and collagen properties. Found in tusks of elephants and teeth of mammals such as the hippopotamus, walrus, boar, sperm and killer whale, ivory forms layers. It gets strength and rigidity from inorganic components, namely mineralised tissues. The organic element, collagen, helps in the growth and repair of ivory, which has no blood vessels, is porous and absorbs and releases moisture.