Materials and appearance distinguish porcelain

KNIGHT RIDDER NEWSPAPERS
Porcelain is different from other ceramics in two ways: It is made of two ingredients, pure white clay and crystalline minerals, and it is fired at a higher temperature. Porcelain is white and translucent and produces a bell-like ring when you strike it. There are three main kinds of porcelain:
UHard-paste porcelain: Also called true porcelain, it contains only kaolin (the pure white clay) and petuntse (a type of feldspar, or crystalline mineral, found only in China). It can be fired at hotter temperatures than soft-paste porcelain or bone china. When it breaks, it looks the same all the way through.
USoft-paste porcelain: Made with fine clay and glasslike substances. When it breaks, you can see a grainy body covered with a glassy layer of glaze.
UBone china: Made by adding large quantities of calcified bone ash (from burned animal bones) to kaolin and petuntse, the ingredients of true porcelain. Not as hard as true porcelain but more translucent.
Strictly speaking, china is a synonym for porcelain, which was invented in China. However, it is often used loosely to denote any ceramic with a hard, nonporous finish, including stoneware, which is made from a single ingredient, clay.
Fine china refers to porcelain or bone china, but not stoneware.