The word nava means ‘nine’ and ratna means ‘gem’ in the Sanskrit language. Navaratna or Navagraha Jewelry which has all the 9 stones representing the all 9 planets.One can get them set in gold or sliver.
All stones can be of same size.
Navaratna refers to the nine gemstones related to the nine planets used in Vedic astrology.
The Gem stones and their Planetary Representations are–
Red Coral —-Mars
Yellow sapphire ——Jupiter
Blue sapphire —Saturn
Hessonite —Rahu, the ascending lunar node
Cat’s eye — Ketu, the descending lunar node