Necklaces / Pendants by Georgia Wiseman Sphere diameter is 16mm. Features Primary Material : silver Other Materials : citrines Length (inches) : 16, 18 and 20 One of a Kind : No Metal : silver Gems : citrines Hallmarked : No Cleaning InstructionsShould the necklace need cleaning, I recommend using only a soft damp cloth and giving the item a gentle wipe. Do not use any abrashive material on the item.