corundum, History.1, gems, Indian lapidary

The fourth chapter of the Rasa Ratna Samuccaya, presented in Sanskrit with English translation and extensive explanatory notes by Damodar Joshi, is devoted principally to ratnas (gems) and is particularly important for the history of Indian gemology. Nine principal gems are associated with the nine planets: ruby, pearl, coral, emerald, topaz, diamond, sapphire, hessonite and cat’s-eye. The text describes desirable and defective qualities of gems and gives procedures for their śodhana (purification) and māraṇa (incineration) for medicinal use. Individual sections discuss ruby, sapphire, diamond, pearl and other gem materials, including their traditional physical characteristics, varieties, supposed planetary relationships, therapeutic properties and methods of processing. Additional materials treated include sunstone, moonstone, lapis lazuli and quartz (sphaṭika). Joshi’s notes compare the traditional descriptions with modern mineralogical identifications and chemical compositions. The chapter provides unusually detailed evidence for the intersection of gemology, medicine, astrology and alchemy in the Indian rasaśāstra tradition.