This gold locket was a locket owned by Marisa Coulter. Ama, whilst hiding in the cave where Marisa was keeping Lyra Silvertongue, saw Marisa make a beverage which would put Lyra into sleep before cutting a dark blonde curl off Lyra's hair, putting it into the golden locket and bringing it to her lips.
After travelling in an intention craft to the College of St Jerome in Geneva, Marisa went to the President of the Consistorial Court of Discipline, Hugh MacPhail, and talked to him about her daughter. Whenever she said her daughter's name, Hugh noticed, her hand went to the locket around her neck. That night, Hugh sent Brother Louis to Marisa's bedroom where he took the locket from around her neck. Hugh took out the hair and made Louis put the locket back on Marisa's neck. Not daring to try and fasten the chain around her neck, Louis laid the locket on the pillow beside the sleeping woman.
Half of the hair was later used to create a bomb that would destroy Lyra. However, the plan failed and the hair was swept into the wind. The other half was taken by the Chevalier Tialys from Dr Cooper, who was taking the hair to his laboratory at the college. Tialys burnt the hair and scattered the ashes to the wind.