A decade in the past, a humorous cash thriller fell into the fingers 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 have 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 information indicated no cash of that denomination have been minted in Peru that yr — 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’s usually solely a notice of “counterfeit” with no additional element, Dr. Ortega mentioned. “Nobody was capable of present extra details about it.”

Now Dr. Ortega and Fabiola Bravo Hualpa, a doctoral scholar, consider they’ve shed new gentle on the thriller of the coin that got here from nowhere. In a paper printed final yr in the journal Heritage Science, they described how they subjected one of many two recognized 1899 dineros to a barrage of scientific analyses, illuminating its doable 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 coloration and options the identical coat of arms and seated lady that represents the goddess of liberty. And it’s remarkably related in dimension 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 called nickel silver. It’s generally used to make silverware and decorative objects and has a silvery look, however it comprises no silver. Real dineros produced by the Lima Mint, however, 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 suggest that the coin was counterfeited way back, no more just lately, the researchers counsel. Such contaminants are attribute of older alloys due to limitations in expertise on the time. “The refining strategies have 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 broadly used for cash or tokens in Peru at the moment, it’s doubtless that this coin was created overseas, the researchers counsel. Its producer may need due to this fact been wholly unaware that no dineros have been formally minted in 1899.

“The counterfeiter in all probability didn’t understand 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 current Battle 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, individuals in Peru have been utilizing cash from neighboring nations and even slicing their very own nation’s cash in half to conduct small transactions. “Counterfeiters discovered a discipline of alternative,” Dr. Ortega mentioned.

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

Dr. Ortega just isn’t completed finding out counterfeit cash and their historic context. He plans to satisfy with a collector based mostly 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 have to be a couple of round,” Dr. Ortega mentioned.