Navajo pearl black onyx necklace. The Navajo pearls are 5mm in size. They are sterling silver. The smooth matte 6mm black onyx round beads and 4mm matte rondelles sit in between sterling silver Bali style spacers. Beautiful southwestern piece. The black and silver combination make this a neutral, versatile and classic necklace that layers well with anything! This necklace is approximately 18.5 inches long.