I know exactly what you mean. Unlikely as it may seem, I have always seen this referred to as "China export porcelain." Meaning, I believe, that it was a type of china which the Chinese made for export.

It was imported in huge quantites on sailing ships at cheap prices. One of the reasons for it's cheapness was that it was actually used as ballast on the trip from China to the U.S. This isn't the only common import used as ballast. The rectangular stones which used to be used for paving streets (often called "cobblestones" which is incorrect -- cobblestones are round) and which are called "Belgian blocks" in Baltimore, were also used as ballast.