How are mixed types seen in China

Glass trade on the Silk Road

The noodles and the gunpowder, the china and the paper come from China - but the glass was not invented in the Middle Kingdom. This fame is due to another region of the world that is also famous for great inventions: the Mesopotamia. Archaeologists have established that between the Euphrates and the Tigris, glass was produced as early as 1600 BC. In China you only got to know glass much later, explains Jiayiao An, archeology professor from Beijing:

"The first glass is probably small pearls and glass inlays for bronzes, very small pieces. They date from around the fifth century BC. They were very valuable back then, we found them in the grave of a rich family. The eye pearls are the most interesting. We analyzed them chemically and found that they consist of a soda glass. That means: The oldest glass in China may come from the West and was not made in China. "

Chemical analyzes can provide an indication of the origin of glass beads, vases or plates, because not all glass is the same. It consists of a large number of chemical elements. The most important component is the quartz sand, which is melted and then allowed to solidify in molds. But quartz is very hard, so you need extremely high temperatures. So that it becomes liquid sooner, a "flux" is added, which lowers the melting point. And this is how researchers can now tell whether a glass was made in China, India or, for example, Egypt. Thilo Rehren, Professor at the Archaeological Institute of the University of London:

"These different types of glass differ mainly in the type of flux that is used to melt the bulk of the glass, namely the quartz. For Egyptian glass, this is primarily the ashes of certain salt plants Roman glass Mineral soda, these are different salts for Indian glass, there are different tree ashes for Central European medieval glass, and this can be seen in the different chemical compositions of the glasses when you analyze them. "

In future, the recipe will be used to determine the place of manufacture. But so far the databases are only sparsely filled with analysis results, explains Dr. Susanne Greiff from the restoration laboratory of the Roman-Germanic Central Museum in Mainz:

"We are at the beginning. We are now compiling data to see where what was used, of course you still have to take the barter into account, so that if you find a glass composition somewhere, you do not assume it directly that it was also produced there. That means you have to collect a lot of chemical data from different places and times in order to be able to make groupings and a good classification. "

After all, it is already clear that there is a lack of soda deposits in China. Soda glasses like the eye pearls from the fifth century BC must have been imported. Nomadic peoples who moved through the countries on the Silk Road could have brought them with them from the West as a means of payment: They exchanged them for food, textiles or whatever they needed, Jiayao An suspects:

"So the glass beads came to China, and the Chinese liked them, especially the rich. And later the Chinese began to imitate the eye beads. They produced glass beads that look very similar and are even more beautifully decorated. But the composition is different: We used lead and barium to make the glass. Because we don't have any soda deposits. "

Glassware did not trigger a boom in China. Although the production was mastered, extensive glass production did not develop as in western parts of Asia and Europe. Instead, the Chinese developed a mastery of coating porcelain with a thin layer of glass, a glaze. They hardly made glass vessels.

"And that is a big question that concerns us together with the archaeologists: Why has this technology been mastered so well and then still relatively little glass is produced as an independent material?"

Glass specialist Jiayiao An has an amazing answer to this problem:

"In China people started using glass in everyday life quite late. Actually only in the present. I think that's because we have very good ceramics. And besides, the Chinese like very hot food, hot soups or drinks!"

And glass dishes are poorly suited for this: the material conducts heat so well that you cannot touch a glass soup bowl or a tea glass without burning your fingers. Porcelain bowls and cups, on the other hand, get less hot. Perhaps that is why china was invented in China: So that you could drink really hot tea!