In ancient China, dating back to at least 5,000 BC, large stone discs were placed on the bodies of Chinese aristocrats. Their original function still eludes scientists, as does the way in which they were made, considering they were carved out of Jade, an extremely hard rock.
Jade is a precious hardstone that is made of different silicate minerals and is often used to make vases, jewelry and other ornaments. It is usually colorless, but contamination from other materials, such as chrome, normally gives it an emerald greenish color. It comes in two main types: nephrite and jadeite. Given the hardness of the stone, Jade is an extremely difficult material to work with, which makes it perplexing as to why the ancient Neolithic inhabitants of China chose this stone.
Since they were made in a period of time in which no metal tools have been found, archaeologists believe they were probably made through brazing and polishing – this would have taken an extraordinarily long time to achieve. So the obvious question here is, why would they go to so much effort?