Source : Webster's Revised Unabridged Dictionary (1913)

Unvalued \Un*val"ued\, a.
   1. Not valued; not appraised; hence, not considered;
      disregarded; valueless; as, an unvalued estate. ``Unvalued
      persons.'' --Shak.

   2. Having inestimable value; invaluable. [Obs.]

            The golden apples of unvalued price.  --Spenser.

Source : WordNet®

unvalued
     adj : having value that is not acknowledged [syn: {unappreciated},
            {unsung}]