Benjamin Franklin Z Grill
The rarest and most valuable US postage stamp. Features a unique horizontal security grill pattern to prevent re-use, with only one copy in private hands.
United States · 1868
Benjamin Franklin Z Grill
Overview
The 1868 1¢ Z Grill is widely considered the rarest, most highly prized, and most valuable postage stamp in United States history. In the late 1860s, postal officials were concerned about people illegally washing cancellation ink off used stamps for reuse. To combat this fraud, Charles F. Steel developed a waffle-like embossing process called 'grilling'. The grill broke the paper's fibers, allowing cancellation ink to soak deeply into the paper. While several grill types (A through J) were used, the 'Z' grill is entirely unique because its ridges run horizontally rather than vertically. It was used for only a few days in late February 1868. Because the 1-cent denomination was primarily used on public notices and circulars, almost all of them were discarded, leaving only two known surviving copies today. One is held by the New York Public Library, and the other, the renowned 'Gross Copy', sold in 2024 for a record $4.366 million.
Design & Technical Details
A 1-cent blue stamp featuring a portrait of Benjamin Franklin. The distinguishing feature is the 'Z' grill embossed waffling on the paper, measuring 11 by 14 mm with horizontal ridges. It is perforated 12.
Historical Facts
- The Z grill was an experimental security measure in use for only a few days.
- Discovered and classified by philatelic expert William L. Stevenson in 1916.
- The Z grill ridges are unique in US philately for being horizontal.
- Traded in 2005 for a $3 million Inverted Jenny plate block to complete Bill Gross's U.S. collection.
- Only two copies exist: the Miller Copy (held by NYPL) and the Gross Copy (in private hands).
How to Identify This Stamp
If you believe you may have found a Benjamin Franklin Z Grill, here are key identification characteristics to check:
- The grill must measure approximately 11 by 14 mm.
- The points of the grill must run horizontally, not vertically.
- Because fakes exist (made by adding a fake grill to a normal 1-cent 1861 stamp), expert certification is absolutely mandatory.
Frequently Asked Questions
What makes the Z Grill so rare?
It was produced for only a few days as an experiment. Plus, 1-cent stamps were used for junk mail and circulars, meaning nearly all were thrown away.
How many 1-cent Z Grills exist?
There are exactly two known genuine copies. One belongs to the New York Public Library, and the other just sold to an anonymous private collector for $4.366 million.
Can I find a Z Grill in my collection?
While infinitesimally small, the possibility exists. However, over 99.9% of found 'Z Grills' turn out to be common E or F grills, or outright forgeries. Authentication is required.