It doesn't work. The cover of crystal glass is a double-layer glass cover, and the isolation layer in the double-layer glass is vacuum, which can play the role of isolation and heat preservation. However, the presence of water means that the glass is cracked and flooded, which can't keep warm, so it can't be used. Glass refers to the cup made of glass, which is made of high borosilicate glass and fired at more than 600 degrees. It is a new type of environment-friendly teacup with smooth surface and easy cleaning, which is more and more favored by people.