Terra cotta is a type of pottery that is unglazed and porous, and usually comes in a natural earthen color, like brown, orange and red. While terra cotta pottery is used in a variety of pieces, from art sculptures to even buildings, one of the most common uses is in flowerpots. Terra cotta is made by firing clay in a kiln once it has been shaken, where the iron in the clay reacts with oxygen resulting in the color change that gives its appearance.