User blog comment:Wilesjeffery2152/Agent Artifact Challenge/@comment-24509764-20140314232351/@comment-4273152-20140319031437

That was a prop made by the writers of Supernatural and doesn't exist. We have Cain's stone in the database, but not in the stacks. I do, however, have an angry polecat on a stick. It would love to meet your face.