According to the surface quality of ceramic products, Chinese building materials standards can be divided into two grades: high-quality products and qualified products. Generally, high-quality products require bricks to be observed vertically at a distance of 0.8 meters without defects, and qualified products are observed at a distance of 1.5 M. Common ceramic defects include pinholes, bubbles, bouncing points, dirt falling, deformation, color difference, cracks, glaze touching, corner breaking, impurities, etc. Defects of qualified products in different batches may vary.