Did you know that there are three different kinds of clay used for pottery? I don't mean that they are all used together, but there are three separate kinds of clay, and each of them are great for pottery. These are kaolin, stoneware, and earthenware. The types of clay used for pottery will determine how it is handled, what will be made out of it, and how hot it will be cooked, or "fired."
Even though these three types of clay have their own characteristics, they do have some things in common. Clay generally comes out of the ground where there used to be a flowing body of water like a river or a stream. It is full of soil, minerals, and plant and animal remains that are broken up as water pressure flows over it. All of these materials become silt. When the silt settles into the ground, clay is created. The distance the silt travels is what makes the difference between each type of clay.
Kaolin Clay
Kaolin Clay is the purest kind of clay because it is close to where is originally developed. In its raw state, it breaks apart easily when bent because the particles are not as worn as with earthenware. It needs a very high fire, which can reach up to 2550 degrees fahrenheit. This clay can become very smooth and shiny, and it is used in porcelain pottery pieces and fine china.
Stoneware Clay
Stoneware is another hard clay, and needs to be fired at a higher temperature. Pottery made from stoneware clay is heated between 2100 and 2300 degrees fahrenheit. This type of clay has a range of colors. It can be light or dark gray, as well as light or dark brown. Stoneware was often used for jugs and dinnerware.
Earthenware Clay
Earthenware clay results from silt and clay traveling with water relatively far from where it originated. It has many impurities, and may contain some sand or tiny rock in its raw state. It tends to be softer. To make pottery with this type of clay, the oven has to be 1700 degrees to 2100 degrees fahrenheit. Pieces of pottery that are common made with earthenware are terra cotta pots and roofing tiles. After it is fired, this type of clay looks white or gray (unless glazed).
Clay is the main ingredient in most pottery today. If you have pottery of your own, you can now appreciate that it all comes from one of Earth's natural processes, and the care of a potter.
