“Man in the Jar,” Damon Knight, 1957 – A man believes a bellhop to be a “Marack,” one of a surviving race of magical natives who can turn coal into diamonds.
Comments: Humorous, perhaps suggests first world arrogance getting a comeuppance. Read in Adventures in Otherness and The Third Galaxy Reader.
Author: Wikipedia: “Damon Francis Knight (September 19, 1922 – April 15, 2002) was an American science fiction author, editor, critic and fan. His forte was short stories and he is widely acknowledged as having been a master of the genre.”