The Question of Ayanamsa .

'Navaratna' Combining the gemstones representing each of the nine planets in Vedic astrology, the navaratna is esteemed by ancient tradition as a bringer of good fortune through its favorable influence on the planetary energies. The most well known design places a ruby, representing the sun, in the center encircled by the other 8 planetary gemstones, diamond for Venus, pearl for Moon, coral for Mars, hessonite for Rahu (the moon's ascending node), blue sapphire for Saturn, cat's-eye for Ketu (the moon's descending node), yellow sapphire for Jupiter and emerald for Mercury.

  Places of Nine Gems & Nine planets.