PLATO Answer:
It was an old fashioned golden locket bearing miniatures of her father and mother with their names and the date of their marriage
It had returned to her sanctified in her eyes; made precious as material things sometimes are by being forever identified with a significant moment of one's existence.
Step-by-step explanation: The description of the necklace as "bearing miniatures of her father and mother with their names and the date of their marriage" indicates the significance of the locket that the girl gave Edmund. She clearly loves him although there is distance between them. This concept is echoed again in the description of the locket as "sanctified in her eyes" when it is returned to her.