Clay is a plastic material that is hand formable at room temperature. The clay that we can shape and use to make things is generally referred to as a clay body and is a composition of various materials, including clay as a mineral.
Clay, the mineral, is the primary raw material that makes up our clay bodies and is also used in our glazes.
Clay is our main source of Alumina (Al2O3) in a glaze. It also contains Silica and chemically bound water molecules. The formula for the clay mineral is Al2O3•2SiO2•2H2O.
Clay particles are thin and flat and have a positive side and a negative side. This causes the minerals to act like little magnets that stick together. It is what gives clay its plasticity.
When fired, the water molecules are driven off and the clay becomes hard and permanent. Fired clay has no plasticity. It doesn’t break down unless it is broken or exposed to geologic time.
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