Hindu Achievements in Exact Science: A Study in the History of Scientific Development c22.s1.4

c22.s1.4

9. There have been different methods of enumeration and classification of the precious gems in different periods. The last important phase is embodied in the "doctrine of nine gems." These are ruby, pearl, coral, emerald, topaz, diamond, sapphire, gomeda (agate or zircon), and vaidurya (chrysoberyl, or lapis lazuli). This doctrine was enunciated probably in the tenth century by the astronomer Shreepati.⁴⁹