NOMISMA
READING A COIN

The Precision and Beauty of Machine-Struck Gold Coins

The Louis d'or, a gold coin born in 1640. Its perfect circular shape, struck by machine, was intended to make it immediately obvious if someone clipped the edges to steal gold. We trace the precision, beauty, and the hidden side of wealth creation embodied in a single coin.

The machine-struck Louis d'or gold coin in 3 minutes

  1. See it
  2. In numbers
  3. What would you do?
  4. Read more

1See it

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1640

In France, the perfectly round Louis d'or gold coin was born.

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Before that

Hand-struck gold coins were irregular in shape. People would shave the edges to steal gold.

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Machine-struck coins had a uniform shape and weight, so any shaving was immediately obvious.

A row of beads and lettering on the edge also made it easy to spot.

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The king's profile was beautifully engraved, like a sculpture.

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1672

Warin became the sole master of the coining machinery.

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March 9, 1661

Around the same time, Chief Minister Mazarin died, leaving behind a huge fortune.

About 35 million livres

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1658

The common people's copper coins lost 1/3 of their face value in about a month.

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September 5, 1661

Superintendent of Finances Fouquet was arrested and imprisoned for life.

2In numbers

22karats

Purity of the gold in a Louis d'or

19,500,000livres

Superintendent Fouquet's fortune. But he also had debts.

Assets19.5 million
Debts16 million

3What would you do?

You are a money changer in old Paris. Someone brings you an old, hand-struck gold coin. Its shape is irregular and the edge isn't clearly defined. What do you do?

Pick one

It's a gold coin, so I accept it as is.

With old, irregularly shaped gold coins, theft by shaving off a little gold from the edges was rampant. It was hard to notice even if a coin had been shaved.

I suspect it might have been shaved.

The machine-struck Louis d'or was designed to make it easy to check for that. It was perfectly round, had a standard weight, and had beads and lettering on the edge. Even the slightest shaving was obvious at a glance.

4Read more

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2026-08-21 Mitsuru Hayama A closer look at coins
France — The louis d'or and machine striking / The Paris mint

Let us begin with a single gold coin: the Louis d'or, created in France in 1640 and named after King Louis XIII. When held in the hand, its perfect circular shape is apparent. This form, uniform to the very edge, had a pressing reason behind it: to protect the credibility of the currency.

The Battle Against Fingers That Clip Edges

In the past, older coins struck by hammer were irregular in shape, with ill-defined edges. This led to the incessant practice of 'rognage'—theft by gradually shaving off metal from the edges.

The screw press, introduced to the Paris Mint by the engraver Jean Varin from Liège, addressed this problem with three mechanisms. First, a perfect circular shape and uniform weight. If even a little was shaved off, it would be immediately noticeable as a flaw. Second, a row of fine beads struck around the edge. Clipping would remove these beads, exposing the tampering. Third was the engraving on the edge itself.

Whereas Japan's Keichō koban indicated its fineness with hallmarks, France sought to prevent tampering through mechanical precision. These were different answers to the same problem of credibility.

From Tool to Sculpture

The protagonist of this reform was not just precision, but also beauty. Under the monetary reform led by the Superintendent of Finances, Bullion, Varin engraved the dies for the gold Louis d'or and the silver Écu blanc.

The profile of Louis XIII that he engraved possessed an artistic refinement unseen in previous coinage. In Varin's hands, the coin—once a mere tool for taxes and war funds—was transformed into a sculpture praising the king. He was later treated as an artist, listed in the Royal Academy, despite being a craftsman who engraved dies.

In the Shadow of the Shining Gold Coin

The machine-struck gold coin eventually became the standard of the country. It was in 1672 that Varin became the sole master of the minting machinery. So, where did the gold for these 22-carat coins come from?

In the era when the Louis d'or was born, a certain cardinal was amassing immense wealth. This was Mazarin, who passed away on March 9, 1661. His estate amounted to about 35 million livres, considered the largest private fortune of the 17th century.

Around the same time, the liard, a copper coin in the hands of the poor, was being devalued. In 1658, its face value was reduced from three deniers to just one denier in the space of about a month, shrinking to a third of its former worth.

The Judged Superintendent

The cardinal's wealth was never judged, but there was one man who was made to play the part of the loser: Superintendent of Finances Fouquet. His fortune had swelled to 19.5 million livres, but it is said that behind this, he had debts of 16 million livres.

On September 5, 1661, the musketeer d'Artagnan arrested Fouquet. The trial resulted in a sentence of banishment, but the king used his power of pardon to change the sentence to the harsher penalty of life imprisonment.

The system of borrowing in advance survived under a different name, and the personal rule of the Sun King began.

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