Rarest stamp
Unique examples include a British Guiana 1 cent black on magenta of 1856 (last on the market in 1980) and the Swedish 3 skilling-banco yellow colour error of 1855.
Rarest stamp
Unique examples include a British Guiana 1 cent black on magenta of 1856 (last on the market in 1980) and the Swedish 3 skilling-banco yellow colour error of 1855.