7 Types Of Clay For Pottery (Explained)

Clay can be found in many places on Earth. There are several different types of clay that have been used for numerous things throughout history, including food, water filtration, and as part of many recipes for pottery.

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types of clay

7 Types Of Clay:

Clay is basically made up of water and silicon (Si), and can be found in several different types:

1. Shale Clay:

A type of rock, also known as a mudstone. Compared to some other types of rocks such as basalt, it is very soft and the particles are very small. It tends to break easily into thin pieces.

This type of rock is much softer than most other rocks and can easily be shaped.

shale-clay

2. Earthenware Clay:

This clay is smooth and becomes hard when fired in a kiln, but it cannot hold water or oil. It comes from shale and has been baked so it becomes more durable. Earthenware clay is porous and usually orange or red. This clay is used to create items that have a glazed finish.

Earthenware-clay

3. Polymer Clay:

Found in India, this type of clay can easily be shaped due to its plasticity—the ability of a substance to change shape when it forces out the matter next to it. It becomes smooth and hard after baking in a kiln. It is made mostly of shale and can hold water or oil, so it’s often used to make pottery items.

polymer-clay

4. Ball Clay:

This type clay has silica (SiO) combined with lime (CaCO). It can be found all over the world and comes from feldspar rocks called Precambrian Age tonalite gneiss. It is white in color and has a very smooth surface. Clays that have high amounts of ball clay can become hard after being fired in a kiln, but the more ball clay it contains, the harder it gets. Ball clays are used to make vitrified non-porous products such as porcelain.

ball-clay

5. Kaolinite:

This soil type is used in making porcelain. It becomes very hard after being treated with heat, but it isn’t suitable for throwing because throwing requires the clay to be plastic and sticky. Kaolin clays are made mostly of aluminum silicate.

Kaolinite

6. Stoneware Clay:

This type of clay made from sandstone or shale. It is found in the United States, Mexico, and China. Like all types of clays, it can be used to create pottery by being mixed with water and then molded. When this clay is fired in a kiln, it becomes hard and durable.

Stoneware-Clay

Stoneware clay is largely composed of quartz particles, contains little or no feldspar, and may have less than 12 % iron oxide. It has a high proportion of silica present in the form of the mineral kaolinite.

This type of clay can be found in China, Mexico, the Unites States, and in Europe.

7. Fire Clay:

This type of clay is used in refractories thanks to its low thermal conductivity and low thermal expansion. It is formed from the chemical weathering of rocks at moderate temperature.

fire clay

Fire clay is relatively impermeable, with a low permeability to water vapor.

When this clay is heated in a kiln, it becomes hard and can be used in pots for baking.

Two factors are important for the production of earthenware clay suitable for pottery, namely plasticity and an appropriate level of water content. The ability to work plastic clay is based on the presence of free silica particles. For pottery applications, low iron oxide levels are desirable.

This type of clay is found in the United States, China, and Mexico. It can be used to create pottery after mixing with water and then molded.

All types of clay are important substances because they are earth’s natural resource.

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