Counterfeit Gold Coins Filled With Platinum: Hollow Gold

The Strange Story of The Hollow Gold Scam:
Counterfeit Gold Coins Filled Real $10 Eagles With Platinum

By Roger W. Burdette – Updated by CoinWeek May 2026

Counterfeit Gold coins have followed real money for nearly as long as coins have existed.

Most counterfeiters used a simple trick. They made a fake coin that looked real, but they struck or cast it from cheaper metal. Then they passed as many pieces as possible before someone caught them[1].

That fraud often worked best with worn silver coins. A fake made from tin or another low-cost metal could pass at a glance. Also, heavy wear helped hide poor workmanship. Therefore, a crude cast piece or a coin struck from weak false dies could still fool busy merchants.

However, some counterfeiters went much further. In the 19th century, they found a way to turn genuine gold coins into dangerous Counterfeit Gold fakes.

Copper-Nickel Coins Created a New Opportunity

Another type of counterfeiting appeared after the United States introduced copper-nickel three-cent and five-cent coins in the latter 1860s.

This scheme did not require gold or silver. Instead, criminals exploited the gap between metal cost and face value. The Mint could produce a five-cent coin from a small amount of copper-nickel and still issue it for five cents. That profit represented seigniorage.

The normal U.S. copper-nickel alloy contained 75% copper and 25% nickel. Yet counterfeiters could buy common “maillechort,” also called “nickel silver,” from scrap dealers or jewelers for only a few cents per pound [2].

They then melted the alloy, rolled it into strips, and cut blanks. Next, they used genuine nickels and three-cent pieces to make counterfeit dies. Finally, they struck the scrap-metal blanks and pushed the fakes into circulation.

Workers often received these pieces. Then they used them for purchases and train fares. As a result, the fraud moved quickly through everyday commerce.

The Gold Rush Gave Counterfeiters a Bigger Prize

During the 19th century, enormous new gold supplies from California and Australia entered commerce. That flow created a bigger target.

In the United States and parts of Europe, counterfeiters developed a far more deceptive method. They did not copy a $10 eagle or $20 double eagle. Instead, they used a real gold coin.

They preserved the coin’s faces. They also preserved most of its edge. Then they removed gold from inside the coin and replaced it with a heavy, cheaper metal such as platinum[3].

To the eye, the coin still looked genuine. In reality, it had become hollow gold.

Why Platinum Worked

Today, platinum ranks as a major precious metal. Industry uses it in electronics and as a catalyst in certain chemical reactions [4]. For much of the past 150 years, however, platinum served a more specialized role. Chemists and assayers prized it because it resisted chemical attack and tolerated high heat.

Pure platinum has a density of 21.45 grams per cubic centimeter. Pure gold has a density of about 19.3 grams per cubic centimeter. Therefore, platinum weighed enough to help a hollowed gold coin meet its expected weight.

Even better for counterfeiters, native platinum often contained impurities, including palladium. Those impurities reduced its density. That made it a practical substitute for gold inside a coin [5].

Treasury Officials Discover Hollow Counterfeit Gold

By 1860, just before the Civil War, the Treasury Department and the United States Mint had learned about a new method of adulterating gold coins with platinum. Contemporary letters called platinum “platina.”

Earlier counterfeiters usually drilled small holes through a coin’s edge. Then they removed gold and inserted platinum plugs. Afterward, they repaired the damaged edge and covered the work with a bit of gold leaf.

The new method proved much more dangerous. It could remove as much as half the gold from a $10 eagle. Worse, it left few visible signs.

The Fraud Described

Dr. John Torrey, Assayer at the New York Assay Office, described the fraud in July 1860:

I procured for you to-day, a fine specimen of a ten-dollar gold coin. It has the proper weight and size, but it is no doubt filled up with platina [i.e. platinum]. It was probably made by sawing through a genuine eagle, and then turning out on a lathe, or filing away, a considerable part of the gold. A disc of platina was then introduced, and a narrow hoop of gold used to fill the saw-cut. The whole was then united with silver solder, and the milling renovated. I have reason to believe there are many of these coins in circulation. We have some ounces of platina taken out of a lot of them, brought to our office. You will have difficulty in finding the seams in the piece I send you. Scarcely a bank in our city would hesitate to take it. I paid five dollars for this piece, which is about its intrinsic value.

Torrey then explained the only reliable test he knew:

Now, how shall we detect these debased pieces? The coinage is genuine, the weight and size correct. I am able to tell them (except when the seams are manifest) only in one way, i.e., by plunging then under nitric acid. This almost immediately acts on the silver solder, producing bubbles of nitrous gas, and a green discoloration around the joint; finally separating the parts completely. A few minutes or even seconds immersion in the nitric acid is generally sufficient to detect the fraud. This method can of course be applied to a considerable number of pieces at once [meaning, ‘at one time’], and the bad ones picked out; the gold ones not being injured by the operation.[6]

How the Counterfeiters Built a Hollow Eagle

Torrey’s description reveals a clever and dangerous process.

First, the counterfeiter sliced a genuine $10 eagle through its edge. Then each half went onto a small lathe. The operator removed gold from the center while leaving the faces and much of the edge intact.

Next, the counterfeiter inserted a platinum disc into the cavity. The fit had to be precise. Otherwise, the restored coin would feel wrong or fail under pressure.

After that, the two halves came back together. The counterfeiter aligned the reeds and joined the coin with silver solder. Then a narrow piece of gold filled the visible saw cut. Finally, the edge reeds received new detail.

A small toothed gear likely handled that final step. A file would have made the work look too irregular. By contrast, a gear could restore reeds that matched the coin’s normal edge.

Torrey paid $5 for the adulterated eagle. He considered that amount close to its intrinsic value. Therefore, if the piece represented the typical fake, the counterfeiter removed about half the coin’s face value in gold.

A Skilled Machinist Could Make Real Money

The work required precision. Yet the necessary equipment already existed in the late 1850s.

A skilled operator could control weight by adjusting the gold band that covered the cut. The only visible seam would appear between that band and the coin’s normal rim [7]. With careful machine work, the finished coin could meet Mint specifications.

A good machinist-counterfeiter might produce five to 10 counterfeit gold fakes per day. With $10 gold pieces, that meant $25 to $50 per day in illicit revenue. With $20 double eagles, the amount could double [8].

That figure mattered. A Philadelphia Mint mechanic earned about $3 per day.

Why Detection Was So Hard

Torrey’s nitric-acid test worked. However, it did not help most merchants.

A clerk in a shop could not easily drop gold coins into nitric acid. A banker also needed speed. By the time an assay office tested a suspect coin, the passer had likely disappeared. Then a merchant or bank held the loss.

So, cash handlers relied on a simpler method: the ring test.

A clerk could drop a suspect coin on a marble counter. Then he listened. A normal struck gold or silver coin forms a solid body. When balanced on a finger and tapped with a fingernail or metal rod, it gives a clear ring.

A hollowed and filled coin does not act like a solid coin. It contains several joined parts. Therefore, it produces a dull “thump” or “thunk,” not the bright sound of a genuine piece [9].

Snowden Looks for a Mint Solution

United States Mint Director James Ross Snowden recognized the danger. He suggested that “reducing the thickness of our gold coinage is the only mode of preventing the debasement in question.”[10]

A thinner, wider coin would make the hollowing method much harder. The Mint ran several experiments. It also produced pattern coins on wide, thin planchets [11].

Edward Pratt Points to the Weakness in the Scheme

A more practical answer came from Edward Pratt, Assistant Treasurer in Boston. He wrote to Treasury Secretary Howell Cobb and focused on platinum supply:

If the Department should determine to employ detectives… it will perhaps be advisable to impart to them the following facts, the accuracy of which can be easily established, viz.: that there are in this country very few purchases of manufactured platina; such being confined almost entirely to dentists and chemists. The Professor of Chemistry at Harvard University informs me that in the course of a year, he uses but about 10 or 12 ounces; and one of the leading dentists if this city tells me that he uses in the same time from six to nine ozs. Much platina is undoubtedly used in the form of crucibles, etc., but it is all manufactured abroad.[12]

Pratt understood the counterfeit gold scheme’s weakness. Platinum did not circulate through ordinary trade in large quantities. Few American businesses bought it. Dentists and chemists used small amounts. Much platinum used in crucibles and similar equipment came from abroad.

Therefore, anyone buying unusual amounts of platinum would draw attention. That fact limited the number of hollow gold coins criminals could make [13].

The Fraud Fades From Mint Attention

In the end, the crisis faded.

Treasury officials worried. Mint officers wrote letters. Pattern coins appeared. Detectives may have received guidance. Yet platinum-filled counterfeit gold coins did not become a lasting flood.

The reason seems clear. The method demanded real coins, skilled labor, precise machinery, and access to platinum. That combination narrowed the field.

Eventually, cut-and-filled gold coins slipped out of Mint and Treasury concern. The letters went into old file cases. The pattern pieces entered the Mint Cabinet of Coins & Medals and a few private collections.

Still, the story remains remarkable. These counterfeiters did not merely counterfeit gold coins. They turned genuine gold coins into traps. For a short time, a $10 eagle could look right, weigh right, and still hide a secret inside.

Notes

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