Crystal is a kind of glass that can be used to make exquisite teacups. Of course, its manufacturing process is very complicated, because it is necessary to cut the crystal into suitable shapes and use special treatment methods to complete the decoration.

First of all, the hardness of crystal is very high and it is difficult to process; Secondly, the cup is an inclined wall with a wide top and a narrow bottom, which leads to complicated processing. Another problem is polishing. Polishing the outer wall is relatively simple, but because the crystal cup is wide on the top and narrow on the bottom, it is difficult to reach in and polish the inside. How the ancient people polished the inner wall and bottom so smoothly is also a problem.