California’s Gold Rush may seem like a far away, bygone era, and these days the phrase “gold digger” more readily brings to mind the opportunistic, money-loving girlfriend maligned by the 2005 Kanye West and Jamie Foxx song than someone searching for riches with a pickaxe and shovel. A gold digger of the traditional kind, however, has just made his or her fortune through the sale of the newly discovered Butte Nugget: just over six pounds of nearly pure gold unearthed from the foothills of California’s Butte County this summer.

The golden nugget was purchased in a private sale last week at the San Fransisco Fall Antiques show, which was, appropriately, gold rush-themed.  The buyer is described as an anonymous historical artifacts collector from the San Fransisco Bay area. While the exact selling price has not been disclosed, Don Kagin, who brokered the sale, told Saving Advice that it was close to the asking price of $400,000.

The value of the nugget’s gold content (it is 80 to 90 percent pure gold) is only about $125,000, but a nugget of that size is now extremely rare, adding significantly to the object’s value. During the California Gold Rush, most large gold specimens were melted down, leaving few in their natural form.

“Nuggets like this don’t come along every day,” said the nugget’s appraiser, David McCarthy, in an interview with CNN. “I really didn’t believe that I would see a California nugget of this size unearthed during my lifetime.”

A modern-day prospector who has chosen to remain anonymous discovered the mammoth chunk of gold in July using a metal detector. It was buried about a foot below the surface on public land. He or she has wisely kept the exact location of the find a secret, to keep other gold diggers from descending upon the site in a gold-crazed frenzy.