A mintmark can change a coin’s value in an instant. In some cases, one small letter turns a common coin into a four-figure rarity. For example, as of April 2, 2026, PCGS lists a 1916 Mercury dime at about $9 in G-4, while a 1916-D starts at about $1,650 in the same grade. That kind of gap explains why counterfeiters still target mintmarks so aggressively.
Unfortunately, counterfeiters have forged, altered, and tampered with mintmarks for decades. Thankfully, collectors can still catch many of these problems with careful study. A loupe, a trained eye, and a few reliable diagnostics often make the difference.
Start With the 1916-D Mercury Dime
The 1916-D Mercury dime offers one of the best lessons in mintmark authentication. PCGS notes that a genuine 1916-D carries a boxy, squared-off mintmark with a triangular opening inside the “D.” The mintmark stands tall. It looks crisp. It also shows the correct shape and placement. Just as important, the issue came from only four reverse dies. Two show repunching on the mintmark, while two do not. Once you learn those shapes and positions, you can reject many bad pieces quickly.
Some Rarities Matter Because the Mintmark Is Missing
Now turn to the opposite problem. Some coins become rare because they lack a mintmark they should have. The 1922 No-D Strong Reverse Lincoln cent stands as the classic example. In 1922, only the Denver Mint struck Lincoln cents, and it produced 7.16 million pieces. PCGS and NGC both confirm that point. PCGS also estimates that about 15,000 examples of the 1922 No-D Strong Reverse survive across all grades.
The variety came from a minting mishap, not from an intentionally low mintage. Heavy die stress and extensive polishing erased the “D” from the obverse die. At the same time, the Mint paired that obverse with a replacement reverse, which left the reverse unusually bold. That chain of events created the famous 1922 No-D Strong Reverse cent that collectors chase today.
Know the Diagnostics on a Real 1922 No-D Strong Reverse
Counterfeiters often tool the “D” off an ordinary 1922-D cent and try to pass it as the rare No-D variety. However, the genuine coin shows a distinct group of diagnostics. The obverse looks weak overall. The “L” in LIBERTY touches the rim. The “TY” in LIBERTY looks stronger than “LIBER.” The words “IN GOD WE” look weaker than “TRUST.” Also, the second “2” in the date looks stronger than the first. Finally, the reverse must look strong. If the reverse looks soft or mushy, collectors should step back and study the coin much more closely.
PCGS breaks 1922-D cents into three groups: standard 1922-D, Weak D, and No D Strong Reverse. That distinction matters because many collectors still confuse the Weak D pieces with the much more valuable Strong Reverse coin. The Strong Reverse remains the key target. Therefore, authentication matters.
Embossed Mintmarks Create a Different Kind of Problem
Missing mintmarks create one problem. Added mintmarks create another. Yet embossed mintmarks may fool buyers most easily because the alteration rises from inside the coin itself. Collectors started seeing this trick in the late 1970s and early 1980s, especially on coins with thick edges and mintmarks near the rim. Buffalo Nickels fit that profile. Morgan dollars do, too.
Take the 1889-S Morgan dollar as an example. Many collectors would not stop at first glance. Some dealers might miss it, too. Yet the market has already seen altered 1889 Morgan dollars with embossed “S” mintmarks. CoinWorld documented one such coin and explained that the altered piece started life as an 1889 Philadelphia Morgan dollar.
What Is an Embossed Mintmark?
An embossed mintmark pushes up from inside the coin. Counterfeiters create it by drilling a tiny hole through the coin’s edge beneath the area where the mintmark should appear.
Then they use a specialized hand tool, often described as plier-like, with the mintmark cut into one jaw and padding on the other. They place the tool inside the drilled opening. Next, they squeeze metal upward from within the coin. After that, they fill the access hole, often with a soft material such as lead, and then sand or sculpt the repair to imitate the original edge. The process takes patience and very fine tools, the sort many collectors compare to dental instruments.
Check the Edge Before You Trust the Mintmark
That leads to the most important defense. Inspect the edge. Always inspect the edge. On a suspect coin, look for breaks in the reeding or disruptions in a plain edge. In the altered 1889-S Morgan dollar discussed by CoinWorld, the reeding below the embossed “S” showed a different depth and appearance. CoinWeek’s counterfeit-detection article makes the same point and adds a useful diagnostic: a genuine 1889-S Morgan dollar should show 186 or 187 reeds. The fake did not.
Specialists can go farther. They can often spot a mismatch in luster and surface texture before they even reach the edge. CoinWorld notes that Philadelphia-struck 1889 Morgan dollars show different luster from San Francisco coins of the same year. So, if the obverse looks like a Philadelphia piece but the reverse shows an “S,” the coin deserves a much closer look.
Why Mid-Range Semi-Keys Still Attract Counterfeiters
The biggest danger does not always sit in the five-figure key dates. Of course, buyers will scrutinize an 1889-CC Morgan dollar. Recent dealer listings place PCGS AU50 examples around $9,150 to $9,562, and recent auction records show AU50 pieces selling from about $6,600 to $7,800. Most collectors expect trouble there.
However, mid-range semi-keys often slip under the radar. The 1889-S Morgan dollar carried a mintage of 700,000 pieces, and CoinWorld correctly describes it as scarce rather than truly rare. Even so, it still commands more money than a routine Philadelphia example. Recent PCGS AU50 dealer listings show 1889-S pieces around $161, while NGC’s March 2026 guide places circulated 1889 Philadelphia dollars around $67 to $82. That spread may not shock a buyer. Still, it can easily tempt a counterfeiter.
That is exactly why these coins matter. Many buyers give a mid-range coin a quick glance and move on. Meanwhile, a skilled alteration can slip through. Collectors and grading rooms have seen enough of these fakes over time that nobody should dismiss them as one-off curiosities.
Knowledge Still Wins
In numismatics, knowledge protects your money. It protects your collection, too. So learn the correct mintmark shape. Learn the placement. Study the edge. Count reeds when the series demands it. Compare luster and strike. Most of all, buy from reputable dealers who inspect coins carefully before they offer them for sale.
Embossed mintmarks represent only one class of alteration. Still, they show how far a counterfeiter will go for the right price gap. Collectors who understand these diagnostics stand a much better chance of catching trouble before it reaches the collection tray.
