An Elanian singer stone is an object of undetermined origin which, when handled by an individual, creates a series of musical tones. The melody it played was different for each individual.
When Sarjenka was brought aboard the USS Enterprise in 2365, she was given an Elanian singer stone, which comforted her in the strange surroundings of the starship. After her memories were erased and she was returned to Drema IV, Sarjenka was left with the stone. (TNG episode: "Pen Pals") Though she had no recollection of how she had gotten it or what it was, it remained a cherished possession. (SCE - What's Past eBook: Progress)