Gold Washington Quarter Mint Error – Struck Over an 1898 $5 Gold Coin
Author’s Note: Mint Error News featured this extraordinary gold quarter on the cover of Mint Error News Magazine Issue 66. At that time, NGC graded the coin PF66, and Mike Byers sold it. The coin has since moved into a PCGS Proof-66 holder. GreatCollections will offer the rarity in an auction that closes September 13, 2026.
Most 1970-S Washington Quarters began life as copper-nickel clad planchets.
This one began life as a $5 gold coin from 1898.
That single fact places this spectacular Proof error in a class of its own.
In 1970, Washington Quarter Proof dies at San Francisco came down on an already completed 1898 Liberty Head Half Eagle. As a result, John Flanagan’s familiar quarter design now sits over Christian Gobrecht’s 19th-century gold coinage.
The two coins came from different centuries. They carried different denominations. They used different metals. Even their standard weights differed dramatically.
Yet somehow, 72 years after the Mint produced the $5 gold coin, it entered a Proof coining operation and emerged as a 1970-S Washington Quarter.
GreatCollections now calls the coin “Believed Unique.” PCGS grades it Proof-66. The coin weighs 8.3 grams.
Two Coins Separated by 72 Years
The physical evidence tells the story.
Under magnification, collectors can still read the 1898 date from the underlying Half Eagle on the reverse. It appears above QUARTER DOLLAR. Additional remnants of the Liberty Head Half Eagle design survive beneath the Washington Quarter design on both sides.
That surviving detail makes the error especially dramatic.
This did not involve a quarter die striking a stray piece of gold sheet. Nor did the press strike a normal gold planchet intended for another denomination.
Instead, the dies overstruck an already coined United States Half Eagle.
The weight provides another powerful clue.
A standard 1970-S Proof Washington Quarter weighs 5.67 grams. PCGS lists its normal composition as an outer alloy of 75% copper and 25% nickel bonded to a pure copper core. The standard coin measures 24.30 mm in diameter.
By contrast, PCGS lists the standard 1898 Liberty Head Half Eagle at 8.36 grams, with a composition of 90% gold and 10% copper. The Half Eagle measures 21.65 mm.
The error weighs 8.3 grams.
In other words, its weight closely follows the original $5 gold host rather than a normal 1970-S quarter planchet.
How Does a 19th-Century Gold Coin Reach a 1970 Proof Press?
That question gives this coin much of its mystique.
The San Francisco facility handled Proof production during this era. Moreover, Proof coinage required far greater control than ordinary circulating production. The U.S. Mint describes Proof coins as special coins made with highly polished planchets and dies. The Mint also notes that Proof coins often receive more than one strike to bring out the design.
My original Mint Error News account also emphasized the hands-on nature of Proof production. Technicians fed blanks into special presses, then workers examined and packaged the finished coins under strict quality controls. Other major Proof errors exist, including broadstrikes, off-center strikes, double strikes, and off-metal pieces. Some have even surfaced in sealed Proof sets.
Therefore, a major Proof error already attracts attention.
A Proof quarter overstruck on a decades-old gold coin moves into another category altogether.
The sources reviewed for this article do not document exactly how the 1898 Half Eagle entered the 1970 Proof production line. The coin itself, however, preserves the result.
The California Proof Error Connection
There is another remarkable chapter to the story.
In my original coverage, I discussed a group of several hundred U.S. error coins that surfaced from a safe-deposit box in the early 2000s. The group included Proof errors as well as errors involving coins intended for circulation.
Error specialist Fred Weinberg purchased the group. The California State Controller’s Office of Unclaimed Property later auctioned the collection.
Before the sale, the United States Secret Service inspected the collection and released it to the State of California, according to my original report. California then sold the coins, and the group dispersed into the marketplace.
That history matters because extraordinary Proof errors can raise obvious questions about how they left Mint custody. In this case, the Secret Service review gave collectors an important legal ownership history for that California group.
Gold Mint Errors Operate in a Different League
Few mint errors can match the visual impact of a familiar denomination appearing on gold.
Several famous pieces help put the Gold Washington Quarter into perspective.
A unique 1913 Type 2 Buffalo Nickel struck on a $5 Indian Half Eagle gold planchet sold for $400,000. That coin weighs 8.33 grams and represents another spectacular case in which dies for a base-metal denomination struck gold intended for a Half Eagle.
Then there is the extraordinary 1915 Panama-Pacific Half Dollar struck in gold. Only two examples are known. A PCGS Proof-64 example from the Bob R. Simpson Collection brought a record $750,000 at Heritage in 2022. Numismatic News reported that the Mint produced the clandestine pattern at Philadelphia on a cut-down Saint-Gaudens Double Eagle.
My original Gold Quarter article also discussed Indian Head Cents struck on $2.50 gold planchets. That article cited six pieces and placed their values at the time between $250,000 and $400,000. Other published Byers listings have cited five known examples, including three dated 1900, one dated 1905, and one dated 1906. Therefore, collectors should treat the six-piece figure as a period roster rather than a settled current census.
Likewise, my original article compared the Gold Quarter with the famous Sacagawea Dollar/State Quarter mule and cited more than 20 examples with then-current values ranging from $100,000 to $250,000. Published PCGS population estimates have varied over time. In 2022, PCGS described roughly 20 known and typical prices around $100,000 to $125,000.
Those changing numbers illustrate an important point. Error-coin populations can evolve as new pieces surface or researchers refine rosters.
The Gold Washington Quarter has not followed that pattern.
GreatCollections still presents the coin as believed unique.
From NGC PF66 to PCGS Proof-66
When Mint Error News first showcased this coin, NGC had authenticated and graded it PF66. It later appeared on the cover of Mint Error News Magazine Issue 66.
Today, PCGS grades the same remarkable error Proof-66. GreatCollections lists PCGS certification number 48183803.
The grade adds another dimension to the story.
A coin can survive more than half a century. A gold coin can survive an additional strike 72 years after its original manufacture. Yet this piece still retains Gem-level Proof quality.
When I first wrote about the coin, I noted how fresh its surfaces appeared despite the extraordinary circumstances of its creation. That remains one of its most striking characteristics.
1970-S Gold Washington Quarter Specifications
- Country: United States
- Date: 1970-S
- Denomination struck: Quarter Dollar
Mint Error: “Gold Washington Quarter” 1970-S Washington Quarter Overstruck on 1898 Gold Liberty Half Eagle - Mint: San Francisco
- Design: Washington Quarter
- Quarter designer: John Flanagan
- Host coin: 1898 Liberty Head Half Eagle ($5)
- Half Eagle designer: Christian Gobrecht
- Composition of host coin: 90% gold, 10% copper
- Error weight: 8.3 grams
- Standard 1898 Half Eagle weight: 8.36 grams
- Standard 1970-S Proof Quarter weight: 5.67 grams
- Standard 1970-S Proof Quarter composition: Copper-nickel clad over a pure copper core
- 1970-S Proof Quarter mintage: 2,632,810
- 1898 Philadelphia Half Eagle mintage: 633,420
- Current grade: PCGS Proof-66
- PCGS certification: 48183803
- Previous certification: NGC PF66
- Rarity: GreatCollections lists the coin as “Believed Unique”
- Auction: GreatCollections
- Closing date: Sunday, September 13, 2026, at 7:07:05 p.m. Pacific Time
A Quarter That Rewrites the Rules
Collectors often use the phrase “coin that should not exist.”
Few coins deserve it more.
For this piece to exist, a $5 Liberty Head gold coin from the McKinley era had to survive for 72 years. Somehow, that already struck coin then reached a San Francisco Proof press in 1970. Washington Quarter dies came down on it. The coin survived the process. It escaped destruction during quality control. Finally, it reached the numismatic marketplace.
Even more remarkably, enough of the original Half Eagle remains visible to prove what lies underneath.
That creates the real “wow” factor.
Look at the reverse closely and two moments in American coinage occupy the same piece of gold. One belongs to 1898. The other belongs to 1970.
GreatCollections will bring those two eras together once again when bidding closes on September 13.
By Mike Byers – Edited by CoinWeek
