Bone ash, primarily composed of calcium phosphate, is a white granular substance produced by calcining animal bones. This process removes all organic material and leaves behind the inorganic mineral component. A common application is in the production of fine china and bone china, lending translucency and strength to the ceramic body.
The inclusion of bone ash enhances the whiteness and chip resistance of ceramic products. Furthermore, it acts as a flux, lowering the firing temperature required in the manufacturing process. Historically, its use dates back centuries, reflecting an effort to improve the quality and aesthetics of pottery and porcelain.