A cup passed on to a grandson was thought to be made of brass, but was instead of gold and about 2,500-years old. At a British auction, it went for $100,000 (£50,000).

Englishman John Webster inherited the cup from his grandfather, a "rag-and-bone" man or junk dealer, and had it stored for years thinking it had little value.

"Because he mainly dealt in brass and bronze, I thought that was what it was made from," Webber told the Bournemouth News and Picture Service. "I put it in a box and forgot about it. Then last year I moved house and took it out to have a look, and I realized it wasn’t bronze or brass.

"I sent it to the British Museum, and the experts there hadn’t seen anything like it before and recommended I had it tested at a laboratory. So I paid quite a bit of money for it to be examined by a lab the museum recommended. And they found the gold dated from the third of fourth century B.C."

The cup is 5 1/2 inches or 14cm high with two female faces looking in opposite directions. Experts from the University of Oxford and Harwell Scientifics dated the cup to the Achaemenid empire in the third or fourth century BC.

The Achaemenid empire was the first of the Persian empires. It ruled over major portions of Greater Iran, and was eventually was wiped out by Alexander the Great in 330 BC.

For a video of the auction and interview with John Webster, follow Gold cup auction sale for £50,000.