A metal detectorist's lucky find has become the Scottish government's gain — and experts say it's the oldest Scotland-made coin ever found.

The 900-year-old coin, which bears the image of David I, a 12th-century king, recently went into the possession of National Museums Scotland (NMS), a public body of the Scottish government.

Pictures of the small coin show it has darkened with age and bears signs of patina, though the symbols are still faintly visible.

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Alice Blackwell, a curator at NMS, told Fox News Digital the coin was found by a metal detectorist near a town called Penicuik, some 10 miles south of Edinburgh, in 2023.

The hobbyist promptly reported the find to Scotland's Treasure Trove Unit.

David I, considered one of the most important leaders in Scottish history, ruled from 1124 to 1153. 

He's known for reshaping the Scottish government, expanding royal authority and being one of the few Scottish kings to be canonized by the Catholic Church.

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In the 1130s, David I introduced Scotland's first coinage. Experts have dated the coin to the 12th century, and no other known Scottish coins are as old — a fact that makes the find particularly significant.

"[David I] took territorial control of Cumbria and its mines, then used the existing English mint in Carlisle to produce the first Scottish coins," said Blackwell. "Henry II later reclaimed the territory for England in 1157."

The small coin bears the image of David I on one side and a cross-based design on the other, Blackwell noted.

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"It also bears an inscription indicating it was minted in Edinburgh, making it the earliest example of a Scottish coin produced from a core Scottish mint," she said.

The curator added that David I later established mints in Perth, Berwick-upon-Tweed, Aberdeen, St. Andrews and Roxburgh in the Scottish Borders.

"His reign [also] included the foundation of royal burghs such as Edinburgh, Perth, Dunfermline and Stirling, and the reorganization of civil institutions."

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The coin is a penny, Blackwell said — but it's difficult to say what it would be worth in modern currency.

"Determining the modern economic value today is complex," she said, adding there were no immediate plans for public display.

Scotland continues to yield interesting archaeological discoveries. 

Months ago, excavators at Culloden Battlefield unearthed new secrets from the final moments of Scotland's bloodiest battle.

At Islay, a remote island off Scotland's western coast, archaeologists found a grand castle affiliated with a long-forgotten medieval kingdom.