"People laugh at metal detectorists. I've had people go past and go, 'Beep, beep, he’s after pennies.' Well no, we're out there to find this kind of stuff, and it is out there."

Terry Herbert, the greatest detectorist of them all.

Since the July day when his detector picked up traces of the hoard beneath a field in Staffordshire, a Midlands county that was at the center of the ancient Anglo-Saxon kingdom of Mercia, Mr. Herbert said, he has been seeing piles of gold in his sleep. Awake, he has quietly celebrated his triumph over all the people who mocked him in the years when a typical day’s finds amounted to little but scrap....

He said that on the day of his discovery he reworked a mantra that he regularly used for good luck. “I have this phrase that I say sometimes — ‘Spirits of yesterday, take me where the coins appear’ — but on that day I changed ‘coins’ to ‘gold.’ I don’t know why I said it that day, but I think somebody was listening.”