In Vedic tradition, the Navaratna is a collection of nine sacred gemstones, each representing one of the Navagraha: Ruby (Sun), Pearl (Moon), Red Coral (Mars), Emerald (Mercury), Yellow Sapphire (Jupiter), Diamond (Venus), Blue Sapphire (Saturn), Hessonite (Rahu), and Cat's Eye Chrysoberyl (Ketu). Wearing all nine together in a single piece of jewelry is believed to balance all planetary influences.