Casein-Kunststoff casein plastic caseïneplastic galalithe kasein kazeinska plastika plastica a base di caseina πλαστικό καζεΐνης פלסטיק עשוי מקזאין Erinoid Galalith Galalith Galalith Galalith Karolith Milchstein casein plastics galaliet galalith kunsthoorn milkstone פוליוויניל כלוריד Thermoplastic molding materials prepared from casein, a natural phosphorous-containing protein found in milk. While trying to make a waterproof coating in 1897, Adolph Spitteler and associate W. Krische of Germany discovered that casein becomes hard and insoluble when treated with formaldehyde. Casein plastics were used for small items such as buttons, beads, buckles, combs, fountain pens, umbrella handles, cutlery handles, and knitting needles; they are often pigmented to simulate ivory, horn, or tortoise shell (AAT).