People are always curious about clay. Where does it come from? How do you make it?
It is a fascinating topic that doesn’t get much press coverage.
Clay is all over the place. You might even find some if you go digging in your backyard. The clay that you find will have a unique set of properties including its workability (plasticity), its firing range (the temperatures it can be safely fired to before it starts doing crazy things like melting), its shrinkage rate (the percentage it shrinks when you fire it), and its color. Ceramicists have specific requirements that they need their clay to fit, so instead of digging around until we find exactly the clay we like, we combine various raw materials to get something that suits our needs.
The materials used to make clay are mined. Each material has different properties. Some make the clay more plastic, others make the clay more white or cause it to mature at a higher or lower temperature.
Testing is the beginning, middle and end of being a ceramicist. We are never done testing.
Making a new batch of clay? Test it.
Trying out a new glaze? Test it.
Firing the same clay in a new kiln? Test it.
Just mixed a new bucket of glaze? Test it.