狐丘，亦称狐刚子，道家炼丹之杰。其生平不详，为晋代人，与葛洪同时期。据今人考证，其著述《五金诀》中，被誉为“最大之外丹黄白师”。他是东汉末年黄白术的代表人物之一，魏伯阳似其师，而葛玄则可能是其弟子。他在化学领域的成就显著，其著作反映了当时中国炼丹术的高水平。
然而，由于他的作品未能完整保存下来，他长期被遗忘。在唐初和唐代的书籍中，如《黄帝九鼎神丹经诀》和《龙虎还丹诀》等，其中保留了他关于黄白术的一些重要佚文。他的主要著作包括《五金粉图诀》（又称《粉图经》、《粉图》、《五金诀》，或名为《狐刚子万金诀》）、《出金矿图录》、《河车经》、《玄珠经》，以及其他几部。
fox-gang-zi, a prominent figure in the Taoist tradition of alchemy. His life is not well-documented, but it is believed that he lived during the Jin dynasty, around the same time as Ge Hong. According to modern scholars, his writings reflect a high level of understanding of alchemical practices during the Han and Jin periods.
Despite his significant contributions to chemistry and metallurgy, fox-gang-zi's works have not been fully preserved. However, fragments of his writings can be found in later texts such as "Yellow Emperor's Nine Cauldrons: Secrets of Alchemical Elixirs" and "Dragon-Horse Reverted Elixir". These texts demonstrate fox-gang-zi's expertise in various aspects of alchemy.
His most famous work is "Five Metals Powder Diagrams", which contains formulas for extracting gold from mercury and other metals. He also developed new methods for refining silver using closed-vessel distillation techniques. Fox-gang-zi was one of the first Chinese alchemists to recognize that water (H2O) could be used as a solvent for dissolving metals.
In addition to his work on metal extraction and purification techniques, fox-gang-zi made important contributions to our understanding of chemical reactions involving lead (Pb). His experiments with lead oxides led him to discover new compounds that were previously unknown at the time.
Overall, fox-gang-zi was an influential figure in early Chinese chemistry who made significant discoveries about metal extraction processes and chemical reactions involving lead.
