Ivory is the teeth of animals. True ivory comes from elephants and mammoth,
but the term is generally applied to the tusks of other mammals as well.
Chemically, ivory is similar to bone and antler, and comprises a collagen
matrix with a mineral component.
Unlike bone, ivory has no blood vessel system, and is therefore more dense.

Please note that all ivory dice in my collection are old/antique dice.
I never purchase ivory dice made after 1900.

You can see more ivory dice in Dice from India

Several old ivory 6-sided dice.

Three marvelous pairs of old chinese 'Lord and Lady dice'.