Feigenbaum, 38, of Virginia Beach, Va., is a rare coin dealer, and the dime he was carrying from San Jose to New York is a 1894-S dime, one of only nine known to exist.

He picked up the dime, one of only 24 known to be coined in 1894 in San Francisco, on Monday from the seller's vault in Oakland. He delivered it to the buyer's vault the following day, in midtown Manhattan.

Feigenbaum said he and the seller's agent will split a 6 percent commission on the deal.

Feigenbaum said he put the dime, which is encased in a 3-inch-square block of plastic, in his pocket. Accompanied by a security guard, he drove to the airport.

Shortly after boarding the plane, Feigenbaum transferred the dime from his pants pocket to his briefcase.

"I was worried that the dime might fall out of my pocket while I was sitting down," he said.

All across the country, Feigenbaum kept checking to make sure the dime was safe by reaching into his briefcase to feel for it.

"It's the Holy Grail of coins," he said.