Why is the silk book of Mawangdui Han Tomb so expensive?

The emperor in silk books. According to the relevant data of the silk book of Mawangdui Han Tomb, the reason why the silk book of Mawangdui Han Tomb is so expensive is because it talks about the emperor. Silk scripts of the Han Dynasty, with 28 kinds of words1.2000, were found in Mawangdui No.3 Han Tomb in Changsha, which recorded Zhouyi, Mourning Pictures, Stories of the Spring and Autumn Period, Nine Main Pictures and The Book of the Yellow Emperor. The Chu silk book of the Warring States Period was found in the Chu Tomb in Changsha, Hunan Province, which recorded the earliest creation myth of China, but unfortunately it was taken away by the Americans.