Police sub inspector D B Sarag of the Nagar police station said that the 23-year-old jobless youth wore a helmet and threatened jeweller Vipul Punamiya with a toy pistol, asking him to part with cash as well as jewellery.
The jeweller handed over a gram of gold as well as Rs 5,000 in cash to the youth, but pounced on him and nabbed him.
He has been charged under Section 392 and Section 452 of the Indian Penal Code, the police said, adding that the case is being probed.