USA – 1c, George Washington, Green, Perf 10, Horizontal Pair – worth US.$.8,500

1c, George Washington, Green, Perf 10, Horizontal Pair, Imperforate Between , Block of six with two pairs at left showing the error and two stamps at right normal, selvage at top and right, bright color

This is one of the rarest of the imperforate-between errors — only one other appeared in Power Search, which was offered in 2000 and then subsequently in the Floyd sale (it has an internal crease).

With 1988 and 2004 P.F. certificates