In ancient times, it was a very broad word ~ let's talk about official seal first! In ancient books, the earliest origin of seal is to show power, that is to say, seal first appeared as official seal. It can be traced back to the Yao and Shun era more than 4000 years ago. Under the Book of Sacrifice in the later Han Dynasty, it is believed that the official seal originated from the three kings of Xia, Shang and Zhou. Therefore, to sum up, the seal began with the king and then spread to officials at all levels to exercise their functions. The seal used by the emperor is called the seal, and the subordinate ministers are all called the seal, so the question is to ask the materials of the minister's seal ~ I sorted it out from the Internet, and roughly said: most of the seals of the Warring States period were cast in copper, and some were carved in jade, but relatively few, so the official seal is probably the bronze seal at that time (and the official seal is a general term for the seals of state institutions, and there is no distinction between emperors and ministers). Then in the Qin Dynasty, there was a distinction between the emperor's seal and the official's seal or seal, and ordinary officials also used copper. The official seals of the officials in the Han Dynasty were all made of gold. According to officials, there were fish buttons and nose buttons (that is, handles). Then the official seals of the Wei, Jin, Southern and Northern Dynasties are roughly the same as those of the Han Dynasty, but the materials are gold-plated and silver-plated seals (tut tut, no comments). After the Tang Dynasty, materials were more abundant, including gold and silver, precious stones, jadeite, coral, amber, beeswax, boxwood, bamboo roots and jade seals. In the Song Dynasty, the seal began to be stamped with words (online seems to mean signing), and the private seal in the Qing Dynasty became a lithograph. As for the official seal,%>_<% (personal reasoning should still be mostly gold, silver and copper), and then the seals of the Republic of China were mostly lithographs, as well as iron, plexiglass, rubber and other materials! The seal of Xiling is more expensive. Well, that's about it. Paper.