The production material is Yixing Zisha, which belongs to sedimentary rock and consists of purple mud, green mud, white mud, yellow mud and red mud, collectively referred to as Zisha (purple sand mud). Zisha is a kind of special clay with fine texture and high iron content. Its molecular arrangement is different from the particle structure of general ceramic raw materials. After being fired at a high temperature of 1200 degrees Celsius, the surface of the product is finely processed and does not require glazing.