狐丘，亦称狐刚子，是一位在中国古代炼丹术中占有重要地位的化学家。关于他的生卒年月和籍贯，史料记载不详，但据现代学者陈国符先生考证，他生活在晋代，与葛洪大约同时期。狐刚子以其杰出的炼丹成就著称，被誉为“最大之外丹黄白师”。他撰写了多部著作，其中包括《五金诀》，这部作品反映了汉末至东汉时期中国炼丹术所达到的高水平。
尽管狐刚子的许多著作未能完整保存下来，但幸运的是，他的一些佚文被后世收集并收录于唐初的《黄帝九鼎神丹经诀》及唐代黄白术专著中。这其中包括《五金粉图诀》（又名《粉图经》、《粉图》、《五金诀》，或称《狐刚子万金诀》）、《出金矿图录》、《河车经》、《玄珠经》等。此外，《通志·艺文略》的记录还提到他撰写了一部名为《金石还丹术》的书籍。
fox-gang-zi, also known as fox-chu, was a renowned alchemist in ancient China. His life details, including his birth and death years and place of origin, are unclear in historical records. However, based on the research by modern scholar Chen Guofu, he is believed to have lived during the Jin Dynasty around the same time as Ge Hong. Fox Gangzi was celebrated for his exceptional achievements in alchemy and was titled "the greatest external elixir yellow-white master." He authored several works, including "The Five Metal Secret," which showcased the advanced level of Chinese alchemy during the Han Dynasty to Eastern Han.
Although many of Fox Gangzi's writings have not survived intact, it is fortunate that some fragments were preserved and included in early Tang Dynasty books such as "The Yellow Emperor's Nine Cauldrons Divine Elixir Treatise" and specialized Tang-era literature on yellow-white techniques. These texts include "The Five Metal Powder Diagram Secret" (also known as "Powder Diagram," "Powder," or "Five Metal Secret"), "Mining Gold Records," River Cartography," and ""Gems' Essence." Moreover, according to the record from Zongji Artifacts Catalogue", Fox Gangzi wrote a volume named ""Gold-Stone Reverting Elixir Techniques".
Fox Gangzi made significant contributions to geology-related knowledge about gold mining methods with his work “Mining Gold Records”. In this book he described how gold can be extracted from rivers using simple methods like panning or sieving through sandbars; however he also discussed more complex processes involving excavation pits or large-scale hydraulic operations.
He further developed an innovative method called “blowing out” which involved blowing air into a hole dug near a riverbank where gold particles were suspected to accumulate causing them to rise up towards the surface where they could be collected with buckets or other containers.
His work demonstrated an understanding of geological principles related to mineral formation; particularly concerning gold deposits within rocks that contain quartz veins filled with pyrite minerals (fool’s gold). By recognizing these signs he could identify potential areas for finding gold deposits thus making him one among few who knew how effectively search for precious metals at that time.
In addition ,Fox-Gang-Zi discovered new ways of extracting metals from ores . For instance ,he invented what might be considered today as smelting furnaces . This process involved heating metal ore at high temperatures until it melted into pure metal form .
Moreover ,he introduced new techniques for refining metallic alloys . Such advancements helped improve efficiency when working with various materials leading ultimately towards better quality products
Furthermore ,his discoveries allowed people learn about different types metals properties especially their melting points allowing them create stronger bonds between elements resulting stronger final product
Thus we see how fox gang zi contributed significantly towards advancing our knowledge regarding metallurgy even though most information available comes only through brief mentions scattered throughout history but still provides valuable insights into world-changing innovations taking place thousands years ago
