Photo: Mira Nittymäki
Artists who work with clay have several options for sourcing it. They can purchase material through suppliers who manufacture a wide range of products or source it from nature. Natural clay or "wild clay" comes in a wide range of colours. These colours are determined by three factors: 1. location, 2. depth of the source and 3. composition of the clay's minerals and enzymes.
Metal oxides are responsible for many clay colours. Iron oxide produces pink, orange-pink, rust-red, and soft green shades. Kaolin produces white tones; ferrous iron adds green-blue tones and illite green tones. Many colours come from organic matter, such as plants, insects, and animals. Potters will tell you these natural colours will alter during the firing process, dulling some and enhancing others. Some dyes have been developed to reinforce the clay's inherent colours, but not all are natural.