Because ivory is different from others, it belongs to bone and looks dense, but it has extremely fine pores and can absorb colored external liquid, and the color has penetrated. Cleaning agents such as toothpaste are useless, and you can't clean the surface after a long time.

In a narrow sense, ivory is the front teeth of African elephants or male Asian elephants [1]. Usually processed into works of art, jewelry or jewelry. In addition, it is also processed into billiards and piano keys, which are very expensive raw materials. Elephant molars and ivory were originally the same substance. Molar is a special structure for chewing. Ivory is a slender tooth that sticks out its lips. They evolved from teeth and are generally used as defensive weapons. In order to protect elephants from being killed, 1973, authorized representatives of 2 1 countries were ordered to sign the Convention on International Trade in Endangered Species of Wild Fauna and Flora, which strictly restricted the ivory trade. China acceded to the Convention on 198 1. However, because ivory trade is a very important economic source for some African countries, and in order to inherit traditional culture such as tooth carving, the Convention approved China and Japan to become legal importers of ivory in 2008.