Indian Alchemy or Rasa Shastra is divided into nine different categories, the first and most important of these is Parada (Mercury). Mercury is considered to be the master metal, it sits at the head of all other rasa base materials. Any rasa medicine containing mercury has its strength increased tenfold. Mercury is generally administered after having being combined with sulphur. In Hindu mythology this union between these elements is attributed to the natural attraction between Lord Shiva and his consort Parvati (Shiva represents Mercury and Parvati represents Sulphur.

The following eight categories of Rasa are as follows: Maha Rasa (Great Rasa) this second category contains eight materials including Mica and Iron Pyrite. Uparasa (Secondary Rasa) this third category contains eight elements including Orpiment and Realgar. Sadharana Rasa (Middle Rasa) this fourth category contains eight elements including Mercuric Oxide and white Arsenic. Dhatu (Metals) this fifth category contains nine elements including Copper and iron. Ratna (Precious Gems) contains nine gemstones including Red Coral and Diamond. Uparatna (Semi precious Gemstones) contains eight gemstones including Tourmaline and Amber.

The eighth category of Rasa is called Visha (Poison) and contains both Aconite and Cobra Venom. The ninth and final category is called Upavisha (Secondary Plant Poisons) and contains plants such as Datura and Nux Vomica.

The image shown (bottom left) is a Damaru Yantra, this apparatus is commonly used to extract mercury from Hingula (Cinnabar). A secondary lid is fixed to the base shown and heated steadily for about three hours. A wet cloth is carefully placed over the top of the Damaru Yantra, allowing mercury vapour inside to collect and condense on the upper lid.