Folks, I need your help here. I dabbled in stamps when I was a kid, but it never stuck and I went the way of baseball cards for my collecting. BUT, my grandfather was a collector when he was a kid, and I was given his collection many years ago when he thought I might be interested in it. Anyway, I have come across this stamp and it seems like it might be rare? Can anyone shed some light on this? It's attached to an album by a stamp hinge., The album is from the mid 1920's. Can I retire with this

, or is it pretty common? Any info at all would be much appreciated.
