It is a kind of glass, made by adding "coloured glaze stone" and "glass mother". Ancient glazed pottery, also called "glazed pottery". It was fired at a high temperature of 1400 degrees. The common types are handmade glass and dewaxed glass, which are colorful and beautiful. Its quality is crystal clear and dazzling. According to legend, the ancient coloured glaze was discovered by Fan Li, the State of Yue, when he was casting a sword in 493 BC. Fan Li thought it was the ultimate creation of heaven and earth, so he gave it to the King of Yue together with the sword. The King of Yue thanked him for casting the sword, returned the original and named it "Li". Later, I visited craftsmen from all walks of life, made the plum into exquisite jewelry and gave it to the stone as a token of love. In the same year, due to the war, scholars went to Wu to defect to relatives. Shi had to give up his feelings and accept justice. When he left, he gave it back to Li. Legend has it that Shi's tears dripped on this "Li", touching the world and the sun and the moon. Tears can still be seen flowing in it, which is called "flowing plum" (glass homonym) by later generations.