1. It can be tapped, and the sound is clear, indicating that the ceramic tile has high density and hardness, and good quality (if the tile makes a “pop, pop” sound, it means that its sintering degree is not enough, and the texture is inferior. If there is a slight “dong dong” sound, its texture is relatively hard compared to the previous one), (actually, the method is very simple. Knock it with your hands, and the high-density tiles will have a crisp fragrance of glass. Density tiles make a…