Last verified: April 2026
Rasa Shastra — Mineral and Metal Medicine
Rasa Shastra is the classical Ayurvedic branch dedicated to the preparation and clinical use of mineral and metal preparations — primarily mercury compounds, metal Bhasma (calcined preparations), and mineral preparations. It emerged as a distinct branch between the 8th and 12th centuries CE, with Rasa Ratna Samucchaya (by Vagbhatacharya, distinct from Vagbhata of Ashtanga Hridayam) as the primary text. The central claim of Rasa Shastra: that properly purified and processed minerals and metals, rendered into bioavailable nano-particulate form through the classical Shodhana-Marana process, produce therapeutic effects impossible to achieve with herbal preparations alone.
The two primary processes
Shodhana (Purification): Every metal or mineral used in Rasa Shastra must be purified before any other processing. Shodhana removes gross impurities, neutralises toxic components, and initiates the transformation from raw material to medicinal substance. Different substances require different Shodhana methods — mercury is purified by trituration with specific herbs; iron by quenching in herbal decoctions; sulfur by melting and straining through cloth in milk.
Marana (Calcination): The purified metal or mineral is mixed with herbal juices, dried, and subjected to controlled heat in a sealed crucible (Musha) inside a Puta (a bed of cow dung cakes of specific size and number). The number of Puta and the temperature determines the fineness and bioavailability of the final Bhasma. The classical Loha (iron) Bhasma requires a minimum of 100 Puta for the highest grade; Swarna (gold) Bhasma requires specific Puta counts documented in classical texts.
Bhasma — the final preparation
Bhasma means 'ash' — the calcined powder remaining after Marana. A properly prepared Bhasma has: extreme fineness (particle size in the nanometre range by modern measurement); complete absence of the original metallic lustre; specific classical quality tests (see below); and the therapeutic properties of the original metal transformed and amplified through the process.
Classical quality tests
Rekhapurna: A small amount of Bhasma placed on the finger and rubbed into the skin lines — it should penetrate the skin lines completely (indicating nano-particle size). Coarse Bhasma sits on the surface.
Varitara: When placed on water surface, Bhasma should float. Metal that has not been properly calcined will sink.
Apunarbhava: The Bhasma cannot be reconverted to its original metal form by any process — indicating irreversible transformation through calcination.
Nishchandra: Complete absence of metallic lustre in the Bhasma — confirming complete calcination.