Iron oxide is one of the most important minerals in clay for giving colour. It is what gives that typical red colour of a brick. A calcareous clay contains more lime and gives a yellow colour. The presence of manganese oxide, by contrast, gives a brown colour to the brick..

What color are bricks?

Most bricks burn to various hues of red: as the temperature increases, this red may progress from dark red, to purple, to brown or grey. Similarly, naturally pink bricks are usually the result of high iron content, while naturally white or yellow bricks are the result of high lime content.

Are bricks red or brown?

Iron oxide is one of the most important minerals in clay for giving colour. It is what gives that typical red colour of a brick. A calcareous clay contains more lime and gives a yellow colour. The presence of manganese oxide, by contrast, gives a brown colour to the brick..