A very fine used single of the 15kr blue Franz Josef from the 1858-1859 Franz Josef Issue, type ii.
Some heavy toning on the back, which might come out with persistent soaking and careful peroxide treatment. I never got around to it, but this is still the nicest example of this stamp I've ever seen.
Scott doesn't list this variety, so we estimate it at $5. The stamp offered here grades 79 as follows:
