Brass Mermaid Diving Necklace. The fabled hybrid creature that resides under the seas never fails to fascinate as it has done so across the centuries from Babylon to Brazil. Our all-metal underwater nymph inside a clamshell is lightweight and impressive at 4.5 inches in length. A brass cha-cha chain and glass ball locket that opens complete the ensemble. Make a splash with this timeless beauty.