Taoist Internal Alchemy

Some of the famous ancient Chinese bronzes actually show xian (so-called immortals) themes. The early writers on the subject who were also xian admirers (such as Zhuangzi and Laozi), mention the kind of practices associated with these people and the results and stages of these practices. They do not mention metallurgy, however. Clear evidence of the connection between metallurgy, alchemy, and xian culture can be found in later writings, such as the Baopuzi Neipian 抱朴子內篇 (Inner Chapters of the Master-Who-Embraces-Simplicity). In this work, Ge Hong writes about jindan 金丹 (gold and cinnabar or golden cinnabar) and we can find recipes and methods to make gold and the immortality medicines. 

Another famous writing containing valuable source material is the Zhouyi Cantongqi 周易參同契 (Identifying the Three as One Following the book of Changes), a Taoist writing on alchemy and cosmology. This and other writings make it obvious that the purpose of the alchemy was was not just making gold (and silver) but the elevation of the alchemist towards heavenly status, which exactly was what the xian were after. The Book of Changes was introduced not as a book on divination but as one on the internal changes of the alchemist's body and its symbols became illustrations of the stages of these changes.