It's not a quality problem. The grouting port is a fixed model, with a small hole on it, a small hole after grouting and a small hole after firing ceramics, which is not a quality problem. Ceramics is the floorboard of pottery and porcelain, and it is also a kind of arts and crafts in China. As early as the Neolithic Age, there were rough and simple painted pottery and black pottery in China. Pottery and porcelain have different textures and characteristics. Pottery, made of clay with high viscosity and strong plasticity, is opaque, with fine pores, weak water absorption and turbid tapping sound.