The San Francisco Mint struck proof Lincoln cents for collectors in 1998.
These pennies featured mirror-like fields and frosted design details known as a deep cameo finish.
Most 1998 proof cents were made using proof dies designed specifically for that year.
A few coins were accidentally struck using a business-strike reverse die instead.
This mix-up created the variety known to collectors as FS-901.
It ranks at number 53 on our list of the 200 most valuable pennies.
A top-quality example of this coin brought $5,160 at Heritage Auctions in February 2024.
The coin was certified in a perfect grade of PR-70.
A PR-70 grade means the coin has zero post-production flaws even under 5x magnification.
Finding modern proof coins with no spots, haze, or scratches is very difficult.
Most known examples of this variety trade for much less in lower proof grades.
The record price reflects the rare mix of an unusual variety and an absolutely flawless grade.
This coin is a classic example of a transitional die error.
In the late 1990s, the Mint used two different designs for the word AMERICA on the reverse.
Business strikes meant for regular pocket change were supposed to have the letters A and M touching closely.
Proof strikes made in San Francisco were supposed to have wide spacing between those two letters.
For the 1998-S FS-901, the Mint used the regular circulation die to strike a proof coin.
Because these dies were never intended for proof production, very few were made before workers noticed.
Lincoln cent specialists actively look for these transitional die varieties to complete their sets.
That strong collector demand keeps prices high whenever a high-grade specimen appears at auction.
Start by looking at the date and the mint mark on the front of the coin.
You need a coin dated 1998 with an S mint mark under the date.
The coin should have a highly reflective proof finish.
Turn the coin over and look closely at the word AMERICA on the right side.
Use a 5x or 10x jeweler's loupe to inspect the letters A and M.
On the rare FS-901 variety, the bottoms of the letters A and M touch each other directly.
On a regular 1998-S proof, there is a clear, visible gap between those two letters.
You can also check the initials FG near the Lincoln Memorial building.
The Close AM variety features initials that sit slightly farther away from the building base.
If you are not sure what you are looking at under a lens, you can use Coin Value Checker to scan the details and get a quick first opinion.
Keep in mind that billions of regular 1998 pennies from Philadelphia and Denver have the Close AM design naturally.
The variety is only rare when you find that Close AM design on a 1998 proof penny from San Francisco.
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