Bone china
Bone china is a British porcelain in which calcined ox bone is added to the body, which gives a very white colour. This was first used by Thomas Frye in 1748 to make a type of soft-paste porcelain.
In the late 18th century, Josiah Spode adopted it and mixed it with china clay and stone to make a harder version to compete with the importation of Oriental porcelain.
It is first fired to a translucent state without a glaze at 1280°C (2336°F) and the glaze-fired at a lower temperature below 1080°C (1976°F).