A metal detectorist in Belgium has unearthed a fragment of a mysterious bronze artifact known as a Roman dodecahedron that is thought to be more than 1,600 years old.

More than a hundred of the puzzling objects — hollow, 12-sided geometric shells of cast metal about the size of baseballs, with large holes in each face and studs at each corner — have been discovered in Northern Europe over the past 200 years.

"There have been several hypotheses for it — some kind of a calendar, an instrument for land measurement, a scepter, etcetera — but none of them is satisfying," Guido Creemers(opens in new tab), a curator at the Gallo-Roman Museum in Tongeren, Belgium, told Live Science in an email.

(Image credit: Kris Vandevorst/Flanders Heritage Agency)Metal detectorist and amateur archaeologist Patrick Schuermans had found the fragment months earlier in a plowed field near the small town of Kortessem, in Belgium's northern Flanders region.

A translated statement by the Flanders Heritage Agency(opens in new tab) said the fractured surfaces of the fragment indicate that the dodecahedron had been deliberately broken, possibly during a final ritual.

"Thanks to the correct working method of the metal detectorist, archaeologists know for the first time the exact location of a Roman dodecahedron in Flanders," the statement said.