Centuries earlier than the Lydia coin in Asia Minor, which was once considered as the earliest metal coin in the world. Therefore, the bronze shell of Shang Dynasty can be well-deserved called "the earliest metal coin of mankind". The copper shell, as its name implies, is a kind of copper coin made by imitating shells. The most representative thing is that it has a shell tooth in the middle of the front. According to whether there are words on its surface, it can be divided into copper cladding and copper cladding.
Materials are decibels, copper and so on. The shape of the casting is very similar to that of the real shellfish, and the volume is small, which is convenient for circulation and carrying. After Qin Shihuang unified the six countries, he abolished all kinds of currencies in the six countries and uniformly minted and issued half a penny.