Vintage White Mother of Pearl Oblong Beaded Necklace

This necklace is absolutely beautiful period the mother of pearl is so pretty and ey catching. Each bead changes with every turn. the necklace is 20". The beads get gradually bigger down the necklace. the latest one is in the mide measures 3/4" long and 1/2" wide. I am not sure what the metal is, and it's a tad bit tarnished. I belive it is feom.the 1950s but it's not stamped, so I'm not sure.