Ivory

Ivory is the same thing as elephant tusks. People used to kill elephants in India and Africa and cut off their tusks, and carve the tusks into beads or small statues. Sometimes they sold the tusks to Egypt, Greece, Rome, or China for wine or silk or glass beads. Most things made of ivory have to be pretty small, smaller than an elephant tusk.

But when people wanted to make big statues out of ivory, they sliced the tusk into thin sheets, and then pinned the sheets of ivory to a wooden statue, to make an ivory statue.
(Today it is illegal in all countries to kill elephants for ivory).

This is an ivory carving of the Greek goddess Artemis, done during the Roman Empire, now in the Cluny museum in Paris

At first most European and Asian artists used Asian ivory, from Indian elephants. But then they realized that African ivory, from African elephants, was easier to carve. Then traders started to buy African ivory, all along the East and West coasts of Africa. Until 1300 AD, people in the Byzantine empire who wanted African ivory traded with the African kingdom of Aksum, so that Aksum stayed a Christian kingdom until the 1300's AD.