‘Incredibly rare’ ancient purple dye once worth more than gold found in UK

Archaeologists working in England have discovered a “mysterious piece” of a purple substance that in Roman times was worth more than gold, researchers said in a press release.

The researchers who discovered the “sweet purple substance” are working on a years-long investigation into the Roman remains of Carlisle, England, a cathedral city in the center of the country. The excavation is being led by Wardell Armstrong, a UK-based environmental, engineering and mining company.

The substance was found during a 2023 excavation in a Roman bath. Remains of the 3rd century building exist on the grounds of what is now a cricket club, according to the press release.

The team worked with the British Geological Society to test the material. Experts from Newcastle University provided further analysis and determined that it was an organic pigment containing levels of bromine and beeswax, according to the release.

These ingredients allowed researchers to identify the substance as “Tyrian Violet,” the color that the Roman Empire associated with its imperial court. The pigment is made from thousands of crushed shells from the Mediterranean, North Africa and Morocco, according to the release, and was “phenomenally difficult” to make and expensive to produce, making it worth more than gold at the time.

The discovery of these materials led researchers to believe that the building being excavated was linked to the court and could even mean that the Roman emperor at the time, Septimius Severus, had visited Carlisle. Frank Giecco, technical director of the organization responsible for the excavation project, said it was an “incredibly rare” find, especially in Europe.

“This is the only example we know of in Northern Europe – perhaps the only example of a solid sample of the pigment in the form of an unused paint pigment in the Roman Empire,” Giecco said in the communicated. “Examples of this have been found in wall paintings (such as at Pompeii) and in some high-ranking painted coffins from the Roman province of Egypt.”