Ivory is found in the tusks of mammoths, walruses, and elephants and is one of the oldest materials used in instrument-making. From the acoustic point of view, however, it is not ideal. Being much denser than wood it is not as good at transmitting sound. A much-coveted material, it can be obtained only by slaying animals. The European Union banned the import of ivory in 1989 and since then it has disappeared as a material from instrument-making.