The Z Grill: America’s Rarest Stamp and the Mystery of Its Tiny Diamonds
A Stamp Born from Experiment
In 1868, the U.S. Post Office was wrestling with a frustrating problem: people were reusing stamps.
At the time, ink cancellations could often be washed off easily so postal officials looked for a physical solution. Their idea? Grilling.
By pressing a small pattern of ridges into the paper, the ink from cancellation marks would soak deeper and make the stamp impossible to clean.
Each pattern was named after a letter of the alphabet -> A, B, C, D… all the way to Z.
Only one design, however, would become legend: the Z Grill.
What Makes the Z Grill Special
The Z Grill was an embossed pattern made up of tiny diamond shapes, pressed horizontally across the stamp surface. It was applied experimentally to a few sheets of 1¢ Benjamin Franklin and 15¢ Abraham Lincoln stamps. But soon after, the grilling technique was abandoned and those few sheets were lost to history.
Today, only two examples of the 1¢ Z Grill are known to exist.
THE Z Grill
(Source: 2-Clicks Stamps)
The Surviving Two
1️⃣ The New York Public Library Copy
Permanently housed in the Miller Collection.
Not for sale.
Regarded as a national treasure.
2️⃣ The Bill Gross Copy
Once owned by billionaire collector Bill Gross, who famously traded it in 2005 for a block of Inverted Jennys.
(We also have blog about that: Inverted Jenny)
The trade was valued at $3 million USD, setting a new philatelic record.
Facts & Figures
Stamp Name 1¢ Z Grill (Benjamin Franklin)
Year Issued 1868
Color Blue
Design Benjamin Franklin portrait
Grill Type Z (horizontal diamond pattern, 11x14 mm)
Quantity Known 2
Estimated Value $3–4 million USD
Material Unglazed wove paper
Rarity The rarest U.S. postage stamp
From Postage to Priceless
When it was first printed, the 1¢ Z Grill cost just that: a penny.
Today, its market value exceeds that of a Rembrandt etching or a small Picasso drawing. Its rarity doesn’t come from luxury or design, but from a forgotten postal experiment, the kind of bureaucratic oddity that history usually erases.
Yet because two stamps survived, it became one of the great stories of human obsession. How something meant to prevent theft became one of the most stolen glances in collecting history.
A Lettre Reflection
At Lettre, we love the Z Grill not just for its rarity but for what it represents:
how a simple innovation invisible to most eyes can make something extraordinary.
Each grill mark is a tiny diamond-shaped memory pressed into paper, a literal imprint of time and intention.
It’s proof that even the smallest details, when preserved, can carry the weight of history.
Final Thoughts
From a postal experiment to a national treasure, the 1¢ Z Grill reminds us that history often hides its greatest treasures in the smallest places —
in ink, paper, and the marks left behind by human hands.
It’s more than a stamp.
It’s a story pressed into paper, forever.
