Where is Clay From?

Clay is one of the most useful materials we get from the earth, and one of the most common minerals. Different types of clay are found all over the world. Some are rare, like the white clay that it used to make porcelain, some are more common, like the soft red clay we use to make flowerpots.

Qualities of Clay

Clay is soft enough to be made into all sorts of different shapes. After you have shaped it you need to put it in a kiln and fire it, this makes the clay hard. After it has been shaped and fired we call it pottery or ceramic.

There are two different types of pottery. The first is called earthenware it is made of a clay which can only be fired at a low temperature (usually about 1000°C) before it goes out of shape or collapses.

The second group can take a higher firing, some up to 1260°C. Then the clay melts or fuses together, becomes smooth, glassy and so tough that they are called stonewares.

 

 

Different clays can also be mixed together. Porcelain is a stoneware made up of different types of white clay. It is unlike any other ceramic. When you hold it up to the light and move your finger about behind it you can see your finger moving. It is translucent.

Ceramics are often coated in glaze, a glassy material which is fixed by a second separate firing. The glaze protects the clay and makes it waterproof.