Z Grill

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Z Grill
New York Public Library Benjamin Miller Collection
Country of production	United States
Date of production	1868 (1868)
Nature of rarity	Limited number
No. in existence	2
Face value	1-cent US
Estimated value	US $3,000,000 (2007)

The Benjamin Franklin Z Grill, or simply "Z-Grill", 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. Although the 1-cent Franklin 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, also with only 2 known to exist. The 10-cent Washington Z-Grill is scarcely less rare with only 6 known to exist. First production runs of Z-Grill process were made of the common Z-grill denominations - the 2-cent Jackson, 3-cent Washington, and 12-cent Washington stamps. The earliest known postmarks of these Z-grill stamps date from January 1868. Then in February 1868 three other denominations were printed with the Z. Grill, the above mentioned 1-cent Franklin, 10-cent Washington and 15-cent Lincoln stamps. These three denominations were only in production for a short period of time with only about 1000 of each being printed before production shifted to the F-grill - resulting in the rarity of these 3 stamps.^[1]

The "Z" pattern, unique among grill templates used by the Post Office because it incises horizontal ridges into the stamp rather than vertical ridges, was replaced within a very short time, for stamps with the D- and E-Grills were already being postmarked in mid-February.^[2]

The purpose of grilling 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 gradually discontinued after 1870.