This is the ealier version of the 10c Washington from the years 1851-1857. Later versions had the number '10' in the top corners. The version without the perforations (on the left) is worth a fraction more than the version on the right.

If you the stamp on the left (without perforations) click here. If you have the stamp on the right (with perforations) click here.

In 1875 the stamp was reprinted, it can be found on hard white paper, perforated and often cut with scissors instead of separated by hand. It is scarce and can be found by clicking here.