Silver 16” necklace with 3 charm drop pendant Used

Used condition, missing one of the diamond chips in middle with gold tone charms above & below the diamond piece with 2 larger single stones on each linked parts. Beautiful necklace & barely noticeable where stone missing & possibly could easily be replaced if u can find one same size & glue in place. I don’t think chain is sterling silver, maybe electroplated? Needs cleaning once in awhile just with a polish cloth. Price reflects the missing stone. Has 4” extension chain that can make length >