Rasa and Rasaśāstra

Rasaśāstra (instructions on mercury) is a body of literature written by alchemists for alchemists in the Sanskrit literary tradition. The classical alchemical scriptures date from no earlier than the tenth century ce; however, the early-7th-century works Aṣṭāṅgahṛdayasaṃhitā and Aṣṭāṅgasaṃgraha prescribe medicinal pastes containing unprocessed mercury and the 9th-century Jain Kalyāṇakara makes mention of purifying and calcining mercury for medicine. In about the eighth century ce, the term rasa-rasāyana (mercurial rejuvenation) first appeared in Buddhist and Hindu tantric texts in reference to the supernatural power (siddhi) of obtaining a magical elixir. The birth of Indian alchemy, as an idea at least, may be traced back to these early medieval sources. This “magical” use of alchemical reagents persisted well into the medieval period in works of tantric practice (see Alchemical Folklore). The earliest systematic alchemical texts, which date from the tenth century, introduced the dual goal of all Indian alchemy: the transmutation of base metals into gold (lohasiddhi) and the perfection of the body to attain immortality (dehasiddhi). The classic Indian alchemical texts were written in the period from the tenth to the thirteenth centuries. These were, for the most part, tantric works inasmuch as their stated goal of achieving an immortal, invulnerable body possessed of supernatural powers aligned with many of the goals of tantric practice and used initiations, deity worship, and mantras in their instructions. As such, the tenth to the thirteenth centuries was the period of “tantric alchemy.” From the thirteenth century forward, mercurial, mineral, and plant preparations came to be increasingly applied to various sorts of medical therapies, many of which complemented the older ayurvedic rasāyana (rejuvenation) treatments. Textual production of rasaśāstra texts continued until the seventeenth century, and they began again in earnest in the early twentieth century with a renewed interest in the sciences and the creation of edited editions based on earlier manuscripts as well as original works. Another offshoot of tantric alchemy was siddha alchemy. In a number of alchemical works, legendary figures called Rasa-Siddhas were evoked as the founders of alchemical lineages and traditions. These were part of a broader medieval religious current, which saw the emergence of several groups self-identifying as siddhas, perfected beings possessed of siddhis. A rich mythology of the siddhas emerged in this period, which portrayed these legendary supermen as combining alchemy with the practice of yoga and tantric techniques. These groups were responsible for internalizing much of laboratory alchemy into yogic practice.