Jade is the common name for two minerals used as gemstones: jadeite and nephrite. In the economic circuit is also nepjade. This is worth less than genuine jade. One can distinguish the two from each other by real jade in a long period of time changes color as the years has been in contact with human skin. Jade has many different colors: green, brown, black or wolkenwit, from very light to very dark. Jade is like soapstone and chalcedony been cut and edited thousands of years by the Chinese. Jade was originally used as a tool but came during the Han Dynasty in vogue as jewelry. The only place where nephrite found in China located in Sinkiang around the city of Khotan. In Chinese culture is only processed jade seen as valuable. A lump of raw jade is of lesser value. In Sanzijing is listed as a comparison with education: "If one does not polishing jade, it is not costly thing if a man does not learn, his life has no meaning, because he knows the norms, values and respect for life is not. and thus will never be accomplished "(玉不琢不成器 人 不 學 不知 義). Jade is considered a valuable stone that wards off evil forces. When carried a long piece of jade on his body, for example a piece of thread around the neck, one will see that the jade slowly changes color. During the 2008 Olympics in Beijing, the medals feature jade.