A decade in the past, a humorous cash thriller fell into the palms of scientists and college students on the Pontifical Catholic College of Peru in Lima.

The college had been buying Nineteenth- and Twentieth-century Peruvian cash from native sellers, and graduate college students within the chemistry division had been analyzing the items for his or her thesis work. However one coin, a 10-cent piece often called a dinero, stood out.

The dinero was marked “1899.” The issue was that official data indicated no cash of that denomination had been minted in Peru that 12 months — in response to the individuals who made the cash, the coin by no means existed.

Most worldwide coin catalogs don’t checklist 1899 dineros, mentioned Luis Ortega, a chemist on the college. And within the uncommon instances that they do, there may be usually solely a be aware of “counterfeit” with no additional element, Dr. Ortega mentioned. “Nobody was in a position to present extra details about it.”

Now Dr. Ortega and Fabiola Bravo Hualpa, a doctoral pupil, imagine they’ve shed new mild on the thriller of the coin that got here from nowhere. In a paper printed final 12 months in the journal Heritage Science, they described how they subjected one of many two identified 1899 dineros to a barrage of scientific analyses, illuminating its potential origins and the position it may need performed throughout an unstable period of South American historical past.

To the bare eye, the 1899 coin resembles different dineros: It’s silver in colour and options the identical coat of arms and seated lady that represents the goddess of liberty. And it’s remarkably comparable in measurement to different dineros minted across the flip of the Twentieth century — concerning the dimensions of a U.S. dime.

However when Dr. Ortega and Ms. Bravo Hualpa bombarded the 1899 coin with X-rays and measured the sunshine it re-emitted, they decided that the dinero was largely product of copper, zinc and nickel. This alloy is named nickel silver. It’s generally used to make silverware and decorative objects and has a silvery look, but it surely accommodates no silver. Real dineros produced by the Lima Mint, alternatively, are roughly 90 p.c silver.

Dr. Ortega and Ms. Bravo Hualpa additionally discovered that the 1899 dinero contained traces of iron, cobalt and lead. These impurities indicate that the coin was counterfeited way back, no more lately, the researchers recommend. Such contaminants are attribute of older alloys due to limitations in know-how on the time. “The refining strategies had been inferior to they’re now,” Dr. Ortega mentioned.

The presence of impurities, paired with the coin’s worn faces, means that it was produced within the Nineteenth or Twentieth centuries, the researchers concluded. However on condition that nickel silver wasn’t extensively used for cash or tokens in Peru at the moment, it’s probably that this coin was created overseas, the researchers recommend. Its producer may need subsequently been wholly unaware that no dineros had been formally minted in 1899.

“The counterfeiter in all probability didn’t notice that that coin didn’t exist,” Dr. Ortega mentioned.

He mentioned that an inflow of low-value coinage would have been welcomed in Peru on the daybreak of the Twentieth century. The nation’s financial system was reeling from the latest Warfare of the Pacific, and the federal government was specializing in printing larger-denomination paper financial institution notes to repay worldwide loans; in 1899, the Lima Mint produced roughly one-tenth the variety of silver cash it produced simply 5 years earlier.

Because of this, folks in Peru had been utilizing cash from neighboring nations and even slicing their very own nation’s cash in half to conduct small transactions. “Counterfeiters discovered a subject of alternative,” Dr. Ortega mentioned.

Dineros had been low-denomination cash utilized by on a regular basis folks. Learning this coin, and the financial and political state of affairs that prompted its creation, can subsequently be illuminating. “If you wish to examine our society, you don’t wish to take a look at a Ferrari,” mentioned Laura Perucchetti, an archaeometallurgist on the British Museum in London, not concerned within the analysis. “You wish to take a look at a Volkswagen or a Ford.”

Dr. Ortega will not be completed finding out counterfeit cash and their historic context. He plans to satisfy with a collector primarily based in Lima who amassed an assortment of cash ostensibly minted from the 1830s by means of the Sixties. One other 1899 dinero has already surfaced in that assortment, and he’s looking out for extra.

“There should be just a few round,” Dr. Ortega mentioned.