DD received a bracelet for her first birthday, and today for her second birthday, got another charm for it. When I pulled out her bracelet, it has discoloured. It is an authentic bracelet, with an authentic charm and it is in it's own original bag with nothing else in there. The silver has gone black in parts on both the charm and the bracelet.

Is this normal? Does it just need a clean, or is there something wrong and it should be returned?