Earthenware
Earthenware teapots are made from clay and are fired at lower temperatures. The lower temperature allows the artist to use brighter, more vivid colors. But it also means that the material is more porous than other ceramic types. Interior glazing can prevent the pot from absorbing the tea and staining.
Stoneware
Stoneware is mostly made of clay but can have up to 10 percent of nonclay materials. Stoneware also is fired at a much higher temperature. This makes the finished material more dense than earthenware. Stoneware is not as porous, very strong and durable.
Porcelain
Porcelain is made from a combination of white clay, silica and feldspar. Fired at the highest temperature, porcelain is the densest form of ceramic. This means that it is largely nonporous and strong enough to be formed into teapots with thin, delicate walls. Porcelain teapots are often referred to as china teapots.