The mystery of the room that shouldn’t exist

Ten years ago, a fictitious money mystery fell into the hands of scientists and students at the Pontifical Catholic University of Peru in Lima.

The university had acquired 19th- and 20th-century Peruvian coins from local dealers, and graduate students in the chemistry department were analyzing the coins for their thesis work. But one coin, a 10-cent coin known as a dinero, stood out.

The dinero was marked “1899”. The problem was that official records indicated that no coins of that denomination were minted in Peru that year – according to the people who made the money, the coin never existed.

Most international coin catalogs do not list 1899 dineros, said Luis Ortega, a chemist at the university. And in the rare cases that they do, there is often just a “counterfeit” note with no further details, Dr. Ortega said. “No one has been able to provide more information on this.”

Now, Dr. Ortega and doctoral student Fabiola Bravo Hualpa believe they have shed new light on the mystery of the coin that came from nowhere. In an article published last year in the journal Heritage ScienceThey described how they subjected one of two known dineros from 1899 to a barrage of scientific analysis, shedding light on its possible origins and the role it might have played during an unstable era in history South American.

To the naked eye, the 1899 coin looks similar to other dineros: it is silver in color and features the same coat of arms and seated woman that represent the goddess of liberty. And its size is remarkably similar to other dineros minted at the turn of the 20th century – about the dimensions of a US penny.

But when Dr. Ortega and Ms. Bravo Hualpa bombarded the 1899 coin with X-rays and measured the light it re-emitted, they determined that the currency was largely composed of copper, zinc and nickel. This alloy is known as nickel silver. It is commonly used to make silverware and ornamental items and has a silvery appearance, but it does not contain silver. In contrast, real dineros produced by the Lima Mint are approximately 90% silver.

Dr. Ortega and Ms. Bravo Hualpa also discovered that the 1899 dinero contained traces of iron, cobalt and lead. These impurities suggest the coin was counterfeited a long time ago, not more recently, the researchers suggest. Such contaminants are characteristic of older alloys due to the technological limitations of the time. “Refining methods were not as efficient as they are today,” Dr. Ortega said.

The presence of impurities, coupled with the worn faces of the coin, suggests that it was produced in the 19th or 20th century, the researchers concluded. But given that nickel silver was not widely used for coins or tokens in Peru at that time, it is likely that this coin was created abroad, the researchers suggest. Its producer was therefore perhaps completely unaware that no dineros were officially minted in 1899.

“The counterfeiter probably didn’t realize this part didn’t exist,” Dr. Ortega said.

He said an influx of low-denomination coins would have been welcome in Peru at the dawn of the 20th century. The country’s economy was reeling from the recent Pacific War and the government was focused on printing higher denomination paper banknotes to repay international loans; By 1899, the Lima Mint was producing about one-tenth the number of silver coins it had five years earlier.

As a result, people in Peru used coins from neighboring countries or even cut their own country’s coins in half to make small transactions. “Counterfeiters have found an area of ​​opportunity,” Dr. Ortega said.

Dineros were low-value coins used by common people. The study of this piece and the economic and political situation which motivated its creation can therefore be enlightening. “If you want to study our society, you don’t want to look at a Ferrari,” said Laura Perucchetti, an archaeometallurgist at the British Museum in London who was not involved in the research. “You want to look at a Volkswagen or a Ford.”

Dr. Ortega has not finished studying counterfeit coins and their historical context. He plans to meet with a Lima-based collector who has amassed an assortment of coins apparently struck between the 1830s and the 1960s. Another dinero from 1899 has already surfaced in that collection, and he is looking for others.

“There must be a few around,” Dr. Ortega said.