Scientists Use Earth's Magnetism to Spot Fake Pottery

Forgers just got a much harder job, thanks to scientists who discovered how to tell ancient pottery from modern fakes using Earth's magnetic field.

Researchers at the Scripps Institution of Oceanography at UC San Diego developed a test that reads magnetic signatures locked inside clay. When ancient pottery was fired in kilns centuries ago, the clay captured the direction of Earth's magnetic North Pole at that exact moment in history.

Here's the clever part: Earth's magnetic pole constantly shifts position over time. Ancient pottery points toward where the pole was hundreds or thousands of years ago, not where it is today.

But there's more. After the pottery cools, it slowly picks up a second, weaker magnetic signal from being exposed to Earth's field for centuries. Scientists call this viscous remanent magnetization, or VRM for short.

The research team tested 45 pottery samples, from ancient storage jars excavated in Israel to modern souvenir vessels sold in Jerusalem. They heated each piece gradually and measured when its weaker magnetic signal disappeared.

The results revealed a clear dividing line. Any pottery older than a thousand years had to be heated to at least 234 degrees Fahrenheit before its centuries-old magnetic signal vanished. Modern pottery lost its signal at much lower temperatures.

"The resolution we require is not very high; we just want to know if an object is ancient or modern," says study co-author Yoav Vaknin.

Why This Inspires

This discovery arrives at a critical moment. Fake artifacts flood markets in archaeologically rich countries from Israel to China to Mexico. Museums struggle to know what's real, and criminal networks profit from looted treasures.

The team already put their method to work, testing three questionable artifacts confiscated by the Israel Antiquities Authority. All three turned out to be genuinely ancient, possibly items that had been illegally looted and trafficked.

"I hope that our new method will be useful for museum curators who wish to display only authentic artifacts, for archaeologists and historians studying the societies which created them, and for law enforcement authorities in their effort to eliminate illicit antiquities trade," Vaknin says.

The technique could help resolve cases like the controversial "James Ossuary," a burial box that supposedly belonged to Jesus Christ's brother but faced forgery accusations that couldn't be proven in court.

Science just gave the good guys a powerful new tool in the fight to protect human history.