The use of porcelain made from bone ash in Islam depends on certain conditions. The most important factors are the source of the bone ash and how the animal from which it was derived was slaughtered. While bone ash in porcelain production is commonly obtained from cows, other animals may also be used.
According to the Hanafi school, using porcelain made from bone ash is permissible if the bones undergo a process of istihāla (chemical transformation) that purifies the material. However, according to the Shafi’i school, since a substance that is inherently impure cannot be purified through istihāla, using such porcelain is not permissible.
To avoid disputes, it is recommended to choose porcelain products made from bones of animals that are permissible to eat and slaughtered according to halal methods.