Last century billiard balls were made from ivory from elephant tusks. In the 1860’s billiard ball manufacturers in the United States became concerned because elephants were being shot in large numbers in Africa to harvest the ivory, rapidly depleting the potential supply, and killing far too many elephants. One firm in America offered a prize of $10,000 to anybody that could come up with an alternative to ivory.
In the early 1900’s New Zealand was a major dairy producer, manufacturing butter and cheese for the world. This meant there was an abundance of skim milk and curds, which apart from being used for pig feed, was often thrown out.
The first plastics were developed in 1862, and around 1890 a German inventor named Adolph Spitteler discovered a dairy product named Casein.
Casein is a high quality milk protein product, produced by precipitation of the Casein from pasteurized skimmed milk. Casein is similar to celluloid, and can be highly colored, is easy to grind, sand, and file, but, it without the risks of flammability or toxic fumes that celluloid has. Casein has been described as "the most beautiful of plastics" and was produced in a wide variety of colours including delicate pastel shades, pearls and mottles, especially those imitating tortoiseshell and horn.
The first Casein was produced in a New Zealand factory in 1912. By 1914, 22 dairy factories were making Casein. Casein was also used in England to produce glues, pens, knife handles, and buttons.
Casein can still be found today at a few knife supply stores and online.