A coin owned by generations of a California family has been confirmed by numismatists as one of 12 known quarter eagle coins that were made of Gold Rush ore in 1854 at the San Francisco Mint. "The coin is only about the size of a dime and contains just one-eighth ounce of California gold, but I guarantee it will be worth much more than its weight in gold when it's sold at the auction," said John Kraljevich, director of research at American Numismatic Rarities of Wolfeboro, which authenticated the coin and will auction it.

"You get a sense of the raw frontier, the forty-niners and everything else when you hold a coin like this," he said. Mr. Mudd said the attraction for collectors and investors would push the price to more than $150,000. The auction is on Sept. 18 in Beverly Hills, Calif.