Rasaśāstra — Indian iatro-chemistry

Rasaśāstra, the medieval Indian science of metal and mineral preparations in medicine, systematised between the 8th and 13th centuries in a Sanskrit corpus attributed to Nāgārjuna (the Rasaratnākara), Govinda Bhagavatpada (Rasahṛdaya Tantra), and later the Rasaratnasamuccaya of Vāgbhaṭa II (c. 1300). Its central technique is the detoxification (śodhana) and incineration (māraṇa) of mercury, gold, silver, iron, copper and tin into bhasmas — bioavailable oxide-ash preparations still used in classical Āyurveda and Siddha. The eight-stage mercury process (aṣṭādaśa saṃskāra) is the paradigm; the Siddha parpam and ceṉṉīram preparations are its Tamil analogue.