What makes a postage stamp valuable

Treasured for their flaws "... Much of coin, currency and stamp collecting, in fact, is based on glorious goofs — everything from inverted images to double and triple strikes in coins to misalignment, fold or crease errors with stamps, Holland says. Take the 1918 24-cent U.S. Airmail stamp with an inverted center showing an early biplane upside-down, for instance. The "Inverted Jenny" is one of the best-known examples of an "invert." ..." [Reference: www.capecodonline.com]

Rare invert stamp sells at record $1.2 Million

Philip Weiss Auction Sells Rare Invert Stamp From 1869 For Record $1.2 Million "... a rare "invert" American stamp from 1869 depicting the signing of the Declaration of Independence to a record $1.2 million at Philip Weiss Auctions this past Saturday, February 9 ..." [Reference: antiquesandthearts.com]