Z grill stamp: spot the rare 1867 grill and its value

What a Z grill is, and why you probably do not have one

A Z grill is one of the grill patterns pressed into United States stamps in 1867 and 1868. Look at the back of a grilled stamp and you see a small rectangle of tiny pyramid points. On a Z grill the top of each pyramid carries a ridge that runs sideways. On every other grill the ridge runs up and down, or the point looks like an X.[1]

Six denominations exist with the Z grill: the 1c Franklin, 2c Jackson, 3c Washington, 10c Washington, 12c Washington and 15c Lincoln, catalogued as Scott 85A to 85F.[3][4][12] The 1c and 15c are known in two copies each. Siegel Auction Galleries counts six of the 10c.[1] The other three are scarce, but not unique.

The odds are against you. The common E grill was applied to millions of stamps and looks almost identical at a glance.[1][6] This guide shows how to tell them apart, what dealers are asking for each type on October 28, 2026, and when to stop handling the stamp and send it to an expert.

Why the Post Office embossed a grid into stamps

Charles F. Steel, a supervisor at the National Bank Note Company, is credited with a process that pressed a waffle-like pattern into the stamp. The pressing broke the paper fibers so cancelling ink would soak in, which made it hard to wash a cancellation off and reuse the stamp.[2]

The company tried several sizes. A grill covering the whole stamp weakened it, and a small one did not do the job.[2] That trial and error is why there are so many grill types. Grilling was gradually discontinued after 1870.[12]

Z is not a place in the alphabet. William L. Stevenson, who classified the grills early in the 20th century, could not place this type in the production sequence, so it got the letter Z.[1] Scott also parked it after Scott 85, which is why the numbers carry suffix letters.

The grill types side by side

Collectors separate the 1867-68 grills by two things: whether the points stand up or down, and how many columns and rows of points the grill has. For the Z grill the deciding trait is ridge direction.[3]

How to check a stamp for a Z grill

Do the check with the stamp dry and unmounted, on a dark matte surface, and handle it with stamp tongs. Never soak or rub it to see the grill better. You can damage the one feature that decides the value.

• Confirm the design and denomination first. The Z grill is known only on the 1c Franklin, 2c Jackson, 3c Washington, 10c Washington, 12c Washington and 15c Lincoln of the 1867 issue. A different denomination cannot be a Z.[3][12]
• Tilt the stamp under a lamp held low and to one side. A grill shows as a rectangle of small bumps and dents, much like a waffle. If you see nothing, the stamp is probably ungrilled. Earlier printings of the same designs came without a grill.
• Use a 10x loupe on the back. Find one point near the middle of the grill and look at its top. A Z grill point has a ridge running left to right across the stamp.[1]
• Compare the size. Z and E grills are the same size, roughly 11 by 13 or 14 mm. An F grill is visibly smaller, about 9 by 13 mm. If the grill area is smaller than the others you have seen, it is most likely an F.[1][6][7][12]
• Look for a second, weaker grill. Some stamps carry a double or split grill, where two impressions overlap. Note it, because overlapping impressions can blur the ridges.[8][11]
• Write down what you found and photograph the back in raking light before you do anything else.

Z grill versus E grill: the mistake that hides rarities

The E grill is the one most often confused with the Z. The two grills are the same size. Only the ridge direction separates them, and it is easy to miss unless you know the stakes.[1]

Siegel notes that collectors and dealers have found Z grill stamps misidentified as the more common E grill. One example: a 15c Z grill was found in a collection in 1961 filed as an E.[1] That does not mean your E is a Z. It means the check takes a minute, and skipping it can cost a lot.

Where the Z grill turned up and how rare each denomination is

Siegel's research suggests the Z was the first grill in regular production, from early January 1868, before a second machine added the D grill about two weeks later. The Z device was replaced by the F grill on March 17, 1868. These dates are inferred from earliest recorded uses. There are no production logs.[1]

The 2c, 3c and 12c came first. In late February 1868 the 1c, 10c and 15c followed for a short run, which explains why those three are the true rarities.[1][12]

Two known 1c Z grill stamps exist. One sold on June 14, 2024, and the other belongs to the New York Public Library's Miller Collection.[1][12] There are two known 15c and six known 10c.[1] The 3c and 12c are the Z grills a dealer was actually pricing on October 28, 2026, as the table below shows.

What a Z grill stamp is worth: dealer asking prices on October 28, 2026

Value depends on grill type first, then on condition and whether the stamp is used or mint. The same 3c Washington design swings from tens of dollars to five figures depending only on the grill. The table shows exact Mystic Stamp Company options.[4][6][7]

Read the price gap before you hope for a Z

Compare the 3c lines. Mystic asked 3,750.00 for a used Z grill single and 47.50 for a used E grill single of the same design. A mint Z grill was listed at 19,500.00 against 650.00 for the mint E.[4][6] The grill type, not the portrait, sets the price.

Mystic also asked 2,650.00 for a used 12c Z grill single and 1,500.00 for a used one with small flaws.[5] For the 1c, 10c and 15c Z grills, no ordinary dealer option was listed on the same date, so there is no everyday asking price to quote.

Do not average these numbers. A used single, a damaged copy and a mint stamp are different items, and a dealer's asking price is not what a buyer finally paid.

The record sale and what it does not tell you

On June 14, 2024, a 1c Z grill from the Bill Gross collection sold at Siegel for a total of USD 4,366,000, the highest price recorded for a US stamp.[9][12] Mystic had bought the same stamp in 1998 for USD 935,000.[11]

That result describes a unique, certified, famous stamp. It says nothing about a 12c or 3c Z grill, and nothing about the E and F grills in your album. Use it for scale, not as a target.

What a phone photo can and cannot show

A photo can help with the first step. It can show the design, denomination, color, cancellation and a visible grill, which narrows the issue. It cannot reliably show the direction of tiny ridges on the back, the exact size of the grill, or whether the paper was altered.

Use the checker below for triage only. It will not confirm a grill type, authenticate a stamp or give a certified grade. If your photo suggests an 1867-68 US issue, move on to a loupe and raking light.

When to stop and ask an expertizing body

If the ridges look horizontal, stop. Do not clean the stamp, hinge it, or try to repair a thin spot. The grill itself is the evidence, and Z grill stamps come with certificates from expertizing organizations because the E grill lookalike is so common.[1]

Submit the stamp to a recognized service such as the Philatelic Foundation, which offers expertizing certificates.[10] The U.S. Philatelic Classics Society publishes research on early US issues and grills and is a good place to learn how specialists describe them.[13] Expect a fee and a wait, and keep your own photographs.

For a stamp that turns out to be an ordinary E or F grill, record the Scott number, condition and cancellation, and compare it against the same format only. The condition grading guide explains how to describe flaws, and the catalog number guide shows how to confirm the Scott number.

Other checks that often matter on the same stamp

A grilled stamp is easy to confuse with other 1860s United States stamps. If you hold an ungrilled Franklin, read the Benjamin Franklin 1-cent guide, which covers a different, later green 1-cent Franklin. Measure perforations with the perforation guide, since the 1867 issue is perf 12.

For other hidden features, see the watermark guide, and for a broader view of what makes a stamp valuable, the stamp errors and varieties guide. To compare ordinary asking prices across issues, use the old stamps price list, and for famous high-value cases see most valuable stamps by country.

Photograph the front of any questionable stamp in even light first. The identify a stamp from a photo guide explains how to do it well.

Frequently asked questions