"I saw in an American newspaper yeterday, that an opera, still unfinished, had been written on the story of 'The Scarlet Letter,' and that several scenes of it had been performed successfully in New York. I should think it might possibly succeed as an opera, though it would certainly fail as a play."
--from The English Note-Books, Sept. 17, 1855
We haven't been able to locate information about the opera Hawthorne read about, but here are some records culled from card catalogs of the New York Public Library and Boston Public Library, listed in alphabetical order by principal author's last name.