The Five Phases of Alchemical Metals 阴真君金石五相类

The compiler is unknown.

According to Chen Guofu's research, it was presumably written by a Taoist Priest of the Tang Dynasty under the pseudonym of Zhenjun Yin (Yin Changsheng of the Han Dynasty).

Consisting of one volume, it is included in the Methods category of the Dongshen Section in The Daozang.

This book elaborates on the method of "matching the categories of metals and minerals, with five types complementing each other" in external alchemy, which is rooted in the Yin and Yang theory ofTaoism. It states that various mineral medicines have distinct Yin-Yang natures due to differences in their producing areas: "Yin mountains produce Yin stones, such as various types of azurite; Yang mountains produce Yang stones, such as sulfur." Alchemy requires combining the Yin-Yang essence of compatible mineral medicines to achieve success. If the medicines are improperly selected or their properties are incompatible, the alchemy will fail.

Thus, the book is divided into twenty chapters, listing the producing areas, alternative names, properties, and methods of subduing and combining compatible mineral medicines (based on their essence), including Jingong (Golden Lord, referring to lead), mercury, azurite, sulfur, lead essence, white cinnabar, emery, nitre, hollow blue (a type of mineral), etc. For example, the first chapter "Gate of Matching Jingong and Its Compatible Substances" states: Jingong is lead; "within lead (Yin) lies Yang, and within this Yang is silver." Huanghua (Yellow Blossom) is the essence of lead, silver is the refined essence of lead, and lead itself is the "flesh"—together forming the "Three Talents" within lead. Only when the Three Talents are complete can it be called "true lead," which can subdue mercury and form a stable substance. "If the lead is not true, the mercury will be difficult to bond with." The content of the other chapters follows a similar pattern.