Well, I have two ideas for clue number three, but I can only justify half the clue with the answer in both cases. I can make the "elvish gem" part work, but not the "unendingly virtuous" part.
Unless - and this is a pretty long shot - "unendingly virtuous" could simply mean it doesn't need to have the ending letter of virtuous - the s - and Imrahil can be derived from Silmaril that way - but an L also has to turn into an H for that to happen.
