The inner layer of sperm whale ivory, however, is much larger. This comes from the casque or epithema of the Helmeted Hornbill, a bird native to the East Indies. This substance is used to make small objects such as buckles and brooches, and is highly valued by the Chinese. In cross section, you can see a bright yellow interior with a scarlet rim. These seeds are the size and shape of a small hen's egg, are very hard, and are solid all the way through.
Vegetable ivory is smooth, takes a good polish, easily absorbs dyes, and is relatively inexpensive.
It is used for small items only, such as dice and buttons. Since about WWII, vegetable ivory has been largely replaced by plastics. Since 1865, when it was first invented by Alexander Parkes, celluloid has been used as an excellent ivory substitute. Casein has also been used. There are a few good books dealing with the identification of ivory.