Eggshell porcelain

Gotheborg as usual provides wonderful insight into this ware. Read more here: http://gotheborg.com/qa/eggshellbasefacts.shtml.

Eggshell porcelain is very fragile and only used for display. It is quite a remarkable feat of ceramic engineering and master-craftsmanship.

It was originally developed in the Northern Song Dynasty, ans was reserved for imperial use during the Ming Dynasty. First the very special-bodied clay (more than 50% kaolin) is slipcast in a mould. Then it is enamelled on the inside and fired to give it strength, then ground down on the outside by an expert potter, then glazed on the outside and fired again.