Diamond dealers on 47th Street are hitting rock bottom — and it’s all millennials’ fault.

The twenty-and thirty-somethings are turning to the Internet to buy engagement rings, squeezing gem sellers in the Diamond District, where empty storefronts and booths are multiplying.

“Everybody’s leaving. There’s no business,” said Michael Abramov, who runs Abramov Jewelry with his brother, Albert. “The whole street is bad.”

Young customers are less into formal fashion statements and not as likely to be impressed by a five-figure slice of ice.

“This generation is a more minimalist generation,” said Ray Moses, who works in the business his father started in 1969, Ben Moses Fine Jewelry Designer.

“They don’t dress,” said Mascha Seiden, who runs Paul Seiden Jeweler and has been on 47th Street since the 1950s.

Instead of roaming from shop to shop, buyers peruse Web sites like Blue Nile where they can chose from a variety of shapes, sizes and settings with the finished product delivered to their doors.

There’s little love for the hustle of the Diamond District, where hawkers walk up and down the street asking passers-by if they’re buying or selling jewelry.

“The customers are running away, scared,” said Albert Abramov, whose family’s booth at 55 W. 47th St. is part of a large jewelry exchange where more than a dozen stalls are empty.

Todd Ingwer, 38, the third generation of his family in Leo Ingwer, a jewelry designer and manufacturer, said the whole vibe needed to change.

“The booth-to-booth almost flea-market mentality down there to me is a relic,” he said. “It’s not the most attractive way to do business today, especially when you’re talking about luxury items.”