What does Amren's Amulet represent?

Amren's Amulet symbolizes Fayre's need for a physical talisman when she is going into the dangerous situation at the prison to question the Bone Carver. Amren says the amulet is the reason she was able to leave the prison, and that it will provide that same assurance for Fayre. Fayre clings to the necklace during the trip. When she returns the amulet, Amren says it has no actual power.