CHURCHILL Private Label Mixed Watermelon Tourmaline Necklace 18K Yellow Gold. Four strands of graduating lengths of watermelon tourmaline faceted rondele beads compose this simple yet elegant necklace. A large polished bevel set cabochon pink tourmaline in 18k yellow gold makes the closure. Length of the necklace starts at approximately 16.5" and graduates to 18 1/2"