The Benjamin Franklin Z Grill, or simply "Z-Grill", is a 1-cent postage stamp

Postage stamp

A postage stamp is a small piece of paper that is purchased and displayed on an item of mail as evidence of payment of postage. Typically, stamps are made from special paper, with a national designation and denomination on the face, and a gum adhesive on the reverse side...

 issued by the United States Postal Service

United States Postal Service

The United States Postal Service is an independent agency of the United States government responsible for providing postal service in the United States...

 in February 1868 depicting Benjamin Franklin

Benjamin Franklin

Dr. Benjamin Franklin was one of the Founding Fathers of the United States. A noted polymath, Franklin was a leading author, printer, political theorist, politician, postmaster, scientist, musician, inventor, satirist, civic activist, statesman, and diplomat...

. 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

Grill (philately)

A grill on a postage stamp is an embossed pattern of small indentations intended to discourage postage stamp reuse. They were supposed to work by allowing the ink of the cancellation to be absorbed more readily by the fibers of the stamp paper, making it harder to wash off the cancellation.- In the...

 pressed into the stamp, creating tiny indentations in the paper. Although the 1-cent Z-Grill is generally cited as the rarest and most valuable of all US postage stamps, the 15-cent Lincoln Z-Grill is just as rare and the 10-cent Washington Z-Grill scarcely less so.