Stonehenge at night.
Stonehenge at night. Andrés Nieto Porras/CC BY-SA 2.0

Researchers have found secret markings on a Neolithic stone in southern England. Before his investigation of Hendraburnick “Quoit,” a large ax-shaped stone, Andy Jones of the Cornwall Archaeological Unit knew that it features numerous cup-marks—round prehistoric engravings common throughout Atlantic Europe. But Jones’s team, which was trying to determine whether the stone was once part of a megalithic structure or tomb, soon discovered nearly 10 times as many engravings the Quoit as was initially thought to hold. The vast majority, however, are only visible under moonlight or the raking light of dawn.

“This large number of cups and lines means that [Hendraburnick ‘Quoit’] is the most highly decorated and complex example of rock art in southern England,” the researchers write. The team also found smashed quartz by the site, suggesting that the rock art may have been part of a larger nighttime ritual that went on for many years.

“Quartz has luminescent properties and reflects both moonlight and firelight,” they write, adding that “these luminescent properties are known to have been deployed in rituals in both the Americas and Australia.”

The intention behind the engravings and the nature of the ritual that may have been associated with them is unknown. But, as The Sun notes, the team may have addressed the question they initially set out to answer. They found evidence that the rock formation was dragged up from a nearby valley, suggesting that the stone was indeed once part of some man-made structure and not just a naturally occurring object of interest.

You can view a scaled-down model of the site below and a map of the engravings here.