this is Lizzy's locket it is her family heirloom. Her biological maternal grandmother gave it to her on the day of her death because her grandmother had ESP and knew what was going to happen to her. she was instructed to put a picture of the person whom she cares the most about.
the powers of the locket let her have improved durability, and if she is in trouble and she breaks it, the locket will give her 60 seconds to have much power but once that it over she will be very weak. the only way to fix it is to use an ink heart. press space to see it on her neck