A deposit of semi-precious Blue John stone has been discovered in Treak Cliff, near Castleton, after a 68-year search.
It was first found by miner John Royse, who promised to show young friend Peter Harrison the exact location the next day, but he fell ill and died before he could pass on the details.
The Harrison family has been looking ever since, and now Peter’s grandson John Turner, 21, has found the ‘treasure’.
John, whose family manage Treak Cliff Cavern, said: “It was right under the ladder that my grandfather put in decades ago.”
Peter, 87, said: “When my grandson phoned to tell me he had found it I couldn’t believe it.”