Last week, Irish-American college student McKenna McFadden was walking down the shoreline of Omey Island, a small, tidal island in County Galway, Ireland. There, she spotted something special lying in the sand: a metal brooch dating all the way back to the 12th century, IrishCentral reports.

McFadden, a film and television major at New York University, is currently participating in a six-week NYU summer study abroad program in Dublin. Around 10 days into the trip, she traveled to Omey Island with her classmates—and while on an island tour led by local archaeologist Michael Gibbons, McFadden stumbled across the ancient piece of jewelry.

McFadden was looking at some rabbit burrows when she stepped back and caught sight of the brooch’s back poking out of the sand. She picked it up, and admired it—but she had no idea she’d discovered a rare historic relic. “Oh cool somebody dropped this,” McFadden recalls thinking to Irish radio news station RTÉ 2fm. “I had no idea what it was.”

McFadden showed the pin to Gibbons, and led him back to the place she originally found it. Later, Galway city heritage officer Jim Higgins examined the artifact and concluded that it was a “kite brooch,” named so for its diamond, kite-like shape, The Irish Times reports.

Hundreds of years ago, the brooch was used to fasten a cloak or a shawl. According to Irish Central, it’s one of only a few such jewelry pieces to ever be discovered in the country.

McFadden won’t be keeping the treasure as a souvenir: The brooch has been entrusted to the National Museum of Ireland, she says. “There was never a question of taking it home,” she told RTÉ 2fm.

[h/t IrishCentral]

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