Ivory, Elephant Tusk
noun
An elephant tusk is the material known as ivory (or just an elephant tusk).
ぞうげ
This is a jukugo word that uses the on'yomi readings of the kanji. You should be able to read this on your own.
印鑑を高級な象牙の物に変えました。
I switched out my name stamp for an expensive ivory one.