Shop › Watermelon Tourmaline Signet Image 1 of 8 Image 2 of 8 Image 3 of 8 Image 4 of 8 Image 5 of 8 Image 6 of 8 Image 7 of 8 Image 8 of 8 Watermelon Tourmaline Signet $700.00 13.77ct AIG Certified Bi-color Watermelon Tourmaline set in Sterling Silver & 14k Bezel. Size 8-8.25 US. Certificate is Included! Add To Cart Added! 13.77ct AIG Certified Bi-color Watermelon Tourmaline set in Sterling Silver & 14k Bezel. Size 8-8.25 US. Certificate is Included!