Galatite, also known as "casein," is a natural plastic derived from milk. It is made through the coagulation of milk proteins, particularly casein, which is then processed into a solid form. Historically, galatite was used to create various items, including buttons and combs, due to its durability and ease of shaping. As a biopolymer, it is considered an early example of sustainable materials before the advent of synthetic plastics.