Ancient Canaanites Added Arsenic to Copper to Create Counterfeit Currency

The toxic chemical gave the metal a luminous sheen, enabling forgers to pass off cheap alloys as silver

Fake money
People may have eventually accepted the mixed alloys as legitimate currency. University of Haifa

Centuries before coins first emerged as currency, people in the southern Levant outwitted their peers with counterfeit tokens, according to an analysis of metal pieces used as money in the eastern Mediterranean region, then known as Canaan, between 1200 and 950 B.C.

As the Times of Israel reports, researchers from the University of Haifa and Hebrew University found eight caches of metal that appeared to have been manipulated to look like pure silver. At the time of the forged currency’s creation, the Egyptians controlled Canaan, though the later part of the period saw the empire’s power steadily decline.

Previous research found that pre-1900 B.C. metal fragments found in the area were 100 percent real silver. But in the early Iron Age, following the collapse of the Hittites and weakening of the Egyptian empire, the disruption of trade routes made silver scarce.

“There was a shortage of silver, probably related to the Late Bronze Age collapse,” lead author Tzilla Eshel tells Live Science’s Tom Metcalfe. “[Counterfeiting] continued after the Egyptians left Canaan, but they were probably the ones who initiated it.”

Metal currency found in caches from the period contained up to 80 percent copper and only small amounts of silver. The people who made the money added arsenic, which gives copper the appearance of real silver.

“Despite the small percentage of silver in the silverware, they were mixed with other substances such as arsenic that made them look silver, which reinforces the hypothesis that in at least part of the period it was a deliberate forgery,” say the researchers in statement translated by the Times of Israel.

Ancient Canaanites Added Arsenic to Copper to Create Counterfeit Currency
The metal fragments were made mostly out of copper, with arsenic added to make the alloys look more like silver. University of Haifa

According to Hannah Brown of the Jerusalem Post, the researchers were unable to determine the silver’s origins, but they identified the copper as the product of mines in the Timna area. The findings, published in the Journal of Archaeological Science, suggest the forgers most likely used local copper to make small amounts of silver money from previous periods last longer. As Aaron Kalman reported for the Times of Israel in 2013, radiocarbon dating has shown that the Timna copper mines were operational by around the tenth century B.C.

The scientists found the caches of counterfeit money in various locations across modern-day Israel, including the ancient cities of Beit She’an, Megiddo and Ashkelon. The amount of arsenic found in each piece was similar, hinting that the creation of the metal alloys was part of an organized counterfeiting effort.

Donald T. Ariel, the head of the Israel Antiquities Authority, tells the Times of Israel that minted coins were only used in the Levant as of the end of the seventh century B.C. Before that, people used “proto-coins”—broken pieces of jewelry or other metal fragments valued based on their weight. This currency system is referenced in Genesis 23, which finds Abraham buying land for the Tomb of the Patriarchs.

“He weighed 400 shekels,” Ariel says. “There were no coins at the time. He weighed pieces of silver.”

The research indicates that the use of false silver continued after Egypt withdrew from Canaan, but the copper source changed from Timna to Faynan. Eshel tells Live Science that what began as forgery may have eventually become an accepted convention for creating currency.

“I don’t think you can produce silver-copper-arsenic ores for over 250 years and that no one would notice, because it corrodes [by turning green] over time,” she explains.

The researchers found that long-distance silver trade began again around 950 B.C., with supplies of the metal coming from Anatolia and the western Mediterranean. Starting around that time, currency was once again made out of pure silver.