Black Beaded Necklace with Oval Pendant and Silver Setting

This 18 inch necklace showcases a strand of small round black beads leading to an oval pendant. there are silver fittings in between some of the beads. The pendant features a smooth black stone set in an ornate silver-toned frame with intricate detailing. I'm not sure if this is silver plate or Sterling. it does tarnish if not kept in a sealed bag.