Three years ago, a then-6-year-old boy named Ben discovered a strange rock on a beach in Sussex, England. He took it home, but then lost track of it. Now, the object has been identified for what it really is: a 50,000-year-old Neanderthal hand axe, reports Live Science.

When James Sainsbury, curator of archaeology and social history at Worthing Theatres and Museum, received an email from Ben's mother about her son's find, he didn't expect the object to be anything special, Sainsbury told Live Science.

Neanderthal hand axes are relatively small and dark two-sided flints, which makes them recognizable, according to Sainsbury. They're clearly distinct from the Middle or Lower Paleolithic finds in Sussex. Neanderthals used these tools for activities such as breaking bones to suck out the marrow.

Sainsbury specifically identified the artifact as a Mousterian hand axe, meaning "it's from that very late Neanderthal period when their days were really numbered in Europe and Britain."

He added that some scholars even suggest that Mousterian hand axes were made by the last Neanderthal generations in that area.

"As far as Sussex is concerned, it's really quite rare," Sainsbury said. "In our museum, we have one example and one only. They're extremely rare because presumably the Neanderthal population density was very low."