Richard Croft found the Ghalali Key from Ghana, and gave to his wife, Amelia Croft as a present. Amelia wore it as a necklace. Amelia had it on during the plane crash in Nepal. It snapped of off Amelia during the crash and was left inside the plane wreck.
Years later Lara Croft needed the Ghalali Key, and returned to the wreck, where she retrieved the artifact just in time before the plane fell in to a ravine. lara used Ghalali Key to reforge Excalibur.