Iron oxide (FeO)
Iron oxide is one of the oldest and most versatile ceramic pigments, known for its ability to produce a wide range of colors including reds, browns, yellows and blacks, depending on the concentration and firing conditions. In ceramics, its behavior varies markedly with kiln atmosphere: in an oxidizing atmosphere, iron oxide tends to produce warm reds and browns, while in a reducing atmosphere it transforms into darker tones, such as deep browns and intense blacks. On the other hand, in low temperature firings, iron oxide usually gives brown or red tones, while in high temperature firings or in reducing atmospheres, it can turn black or dark gray.
This compound is fundamental in stoneware ceramics, where it contributes to the characteristic earthy and reddish tones. Its use is also common in the production of rustic glazes and in traditional Japanese ceramics, where it contributes nuances and textures that enhance the natural aesthetics of the pieces. In addition, iron oxide can generate special effects such as speckling and color variations when combined with other oxides and colorants.
In addition to its use as a colorant, iron oxide is also found in many natural clays, giving clay its characteristic earthy color.Interesting Fact
Iron oxide has been used in ceramics since prehistoric times, and many ancient cultures used it to decorate their pieces, as seen in Egyptian and Greek ceramics.Helpful Tip
Iron oxide can affect the texture of the glazes, so it is important to test to control the level of texture and the exact color you want to achieve in your work.
