All the metal is sterling silver and marked 925 on the back of the bezel. The chain is 20 inches in length. The back of the bezel is open to let the light shine through and illuminate the beauty within. You get the actual item pictured shipped to you in our logo gift box. The length of the sea glass is about 3cm. The color of this piece is a color I have never seen before. It was a hard decision to make a necklace with it.