How did the "butter luster" of ancient porcelain come into being? The more detailed, the better!

Although I am a porcelain collector, I can't give you a detailed answer to this question.

The butter luster you mentioned is only available in Ge Kiln, one of the five famous kilns in Song Dynasty. The reason is related to the glaze formula of Geyao porcelain.

This kind of thing can only be felt if you have seen it with your own eyes. Theoretical things are practical problems that cannot be solved. The so-called practice makes true knowledge. You can go to a big museum, or find someone who collects pieces of Geyao porcelain. Others, such as "Bao Guang" and "Ying Guang", are the luster of ancient porcelain after long-term air contact, such as ultraviolet rays.