Benjamin Franklin Z-Grill Stamp

Fair is fair and the philatelists must be mentioned too. The rarest and most expensive U.S. stamp is the Benjamin Franklin Z-Grill Stamp.

Wikipedia...

The Benjamin Franklin Z-Grill Stamp "...is a 1-cent postage stamp issued by the United States Postal Service in February 1868 depicting Benjamin Franklin. While stamps of this design were the common 1-cent stamps of the 1860s, the Z-Grill is distinguished by having the so-called "Z" variety of a grill pressed into the stamp, creating tiny indentations in the paper. The 1-cent Z-Grill is generally considered the rarest and most valuable of all US postage stamps, although the 10-cent Washington and 15-cent Lincoln Z-Grills printed at the same time as the 1-cent Franklin are also extremely rare.

The purpose of the grill was to permit the canceling ink to be better absorbed into the stamp paper, thus preventing reuse of stamps by washing out the cancellation marks. The use of grills was found to be impractical and they were soon discontinued.

There are currently only two known 1-cent 1868 Z-Grills, both with cancellation marks. One is owned by the New York Public Library as part of the Benjamin Miller Collection. This leaves only a single 1-cent 1868 Z-Grill in private hands.

This 1868 1 cent Z-Grill stamp sold for $935,000 in 1998 to Mystic Stamp Company, a stamp dealer. Siegel Auctions auctioned the stamp as part of the Robert Zoellner collection. Zachary Sundman, the eleven-year-old son of Mystic Stamp Company President Donald Sundman, was the individual responsible for wielding the paddle and doing the actual bidding.

Later, in late October 2005, Sundman traded this Z-Grill to financier Bill Gross for a block of four Inverted Jenny stamps worth nearly $3 million. By completing this trade Gross became the owner of the only complete collection of U.S. 19th century stamps."

I still think Chia Obamas would be a good investment too.