Someone told me during the week that some vegetarians and vegans don’t use bone china teacups. I wasn’t aware of this but it made for some interesting reading about the differences between bone china, porcelain and stoneware. I found out that bone china is made from a translucent white ceramic clay but it is set apart from fine china by containing a minimum of 25% bone ash. The animal bones are burned and ground before it is added to the clay. Bone China tends to be slightly translucent in nature. It is easier to manufacture than fine china, is strong, does not chip easily, and has an ivory-white appearance.
Porcelain is a type of ceramic that is made from kaolin clay. It is also referred to as china or fine china. Kaolin is white clay that retains its white color when fired. It is usually covered with a clear glaze. Porcelain becomes vitrified (glass-like) during the second firing of a two-fire process at temperatures of over 1,300 degrees Celsius. It is considered “vitrified” if it absorbs less than 0.2 percent of its own weight. Porcelain tends to be finer quality than stoneware.
Stoneware is also a type of ceramic but differs in color and also in the way it is fired. Porcelain is fired twice but stoneware is vitrified during a single firing and the temperature is a little lower than used for Porcelain. The finish is warmer in color than Porcelain. An easy way to tell porcelain from stoneware is to look at the bottom rim, porcelain will be white whereas stoneware will be a natural color with a colored glaze on top. Yixing teapots (the famous unglazed porous teapots) are a type of stoneware that is made from clay from the region of Yixing in Southern China.
Finally, earthenware, again a type of ceramic, is made from white porous clay that is fired at a low temperature. It cannot hold water and is more chalky and easier to chip than stoneware. Terracotta is a type of earthenware. It is usually more suited to decorative use rather than household use.