There are many kinds and colours of clays. Most are categorized into the following groups:
Earthenware
- Historically, it is the most-used clay body, since most local clays are earthenware
- It reaches maturity at a low firing range, between 950° C and 1,150° C
- The body is generally porous when fired, while the colour can vary from terra cotta to white
- Examples: Barbara Balfour, Ken Chernavitch
- Earthenware can also be Raku fired, which is a very immediate process using post-firing reduction, resulting in a blackened clay body with metallic-looking glazes
- Example: Steve Robinson
Stoneware
- When fired, this clay resembles stone
- Its firing range is between 1,150° C and 1,300° C, making it hard, durable and impervious to liquids
- It is generally light grey to brown in colour due to its high iron content
- Examples:
- High temperature range: David Krindle, Alan Lacovetsky, Marusia Foster, Steve Jorgenson, Kevin Stafford.
Porcelain
- This clay is known for its whiteness
- It is fired very hot, between 1,250° C and 1,400° C
- When fired, it is a very dense and impervious body that approaches glass
- Examples:
- Mid temperature range: Barbara Balfour, Merilyn Kraut
- High temperature range: Merilyn Kraut, Kathryne Koop, Valerie Metcalfe, Kevin Stafford, David Krindle, Alan Lacovetsky