Cameo Necklace

Brown background with antique white cameo on top raised up from the brown background. Open in the back with c-ring closure. Looks new, estate sale purchase. Chain measures about 16 inches and the cameo measures about 1/2 by 1/2 inch in size counting the outside gold tone area. Not sure as to if this is a plastic or glass bead, I am thinking plastic as it is lightweight.