What hard white translucent ceramic material is used to make china?

China is made up of these materials; Kaolin, Feldspar, Quartz, and ball clay (petunse). Among these Kaolin is the most component and is white in color however feldspar is the hardest element of all as it is rock but the translucence is brought about by Mullite a rare silicate material Al2O32SiO2 or 2Al2O3 SiO2 which matches with the formula of kaolin AI2Si2O5(OH)4. However Kaolin is soft and usually white and because it contains the Mullite a translucent element it answers your question as it is said to usually be soft this time around it could be hard due to other factors including geographical effects and weather plus time.