Michael Arnstein isn’t a member of the British royal family – but given how much his life has been affected by Kate Middleton’s engagement to Prince William, he might as well be.

Arnstein, owner of The Natural Sapphire Company in New York City, is reaping the benefits of the “copycat craze” – a phenomenon whereby a public figure’s particular fashion ensemble triggers an immediate reaction amongst consumers to purchase key elements of the look for themselves.

In the hours and days since the announcement of the royal engagement, Arnstein’s jewelry store has been inundated with orders from around the globe for replicas of Middleton’s 18-carat sapphire-and-diamond ring.

“It’s a very exciting time for people in the sapphire business,” he said, adding that he had no idea the response would be so overwhelming. “It’s the greatest thing that could ever happen to us.”

That this sort of spectacle occurs is unremarkable – in many cases, it’s what retailers and designers expect. Clothing line ABS by Allen Schwartz, for instance, has carved out a business reproducing dresses seen at the Academy Awards and does it with such efficiency that dresses make it from design to department store in mere days.

But there are a number of things about the Middleton-inspired fashion frenzy that make it especially fascinating. For one, the engagement announcement came without warning and retailers and designers have had some difficulty keeping up. In the hours after the announcement, the blue Issa London dress Middleton had worn sold out in boutiques across the world and a $25 (£16) version created a few days later by U.K. supermarket chain Tesco sold out within an hour of becoming available online. Middleton’s ring was swiftly copied by Kenneth Jay Lane and has sold more than 30,000 units via QVC since it debuted on November 20.

Luckily for Arnstein, he didn’t have to produce a replica of Middleton’s ring overnight; he’s had a replica in stock since Princess Diana’s engagement in 1981. But the third-generation jewelry-store owner is strained in other ways – he went from selling one to three rings daily to more than 50 in the 36 hours after the engagement announcement. The surge in demand, while welcomed, has put a strain on his resources.

“We don’t have cash reserves to build our business by 200 or 300% [in a matter of days],” he said.

He also added that, as he seeks to replenish his exhausted materials, he’s finding suppliers have upped their prices.

“Everybody wants a piece of the pie,” he said.

The immediacy and force with which Middleton copycats have stormed the market begs a greater question: What’s really driving the copycats? In a day and age where many women hate being seen in the same dress twice, why are they choosing to purchase a dress that’s been seen by everyone, everywhere multiple times?

Perhaps there’s no person better to ask than Basia Richard, a Los Angeles-based stylist whose goal it is to create looks that consumers covet.

Baby Phat named one of its dresses the Selena Dress for actress
Selena Gomez, who wore it at the 2009 Teen Choice Awards.
(Photo courtesy of BabyPhat.com)

Richard, whose client list includes young Hollywood stars such as Selena Gomez, Hilary Duff and Victoria Justice, said she isn’t surprised by the reaction to Middleton and argues consumers are simply trying to get in on the fairytale.

“People want to feel closer to [Middleton] by buying something similar,” she said. “They want to say ‘I have the same ring that Kate’s got! That makes me feel special.’ I think that’s what the whole phenomenon is.”

Richard acknowledges that the financial impact that a celebrity has on a company often has a longer shelf life than the hype itself. She explained that the one-shoulder purple Baby Phat dress Selena Gomez wore to the 2009 Teen Choice Awards sold so many units that Baby Phat named the dress after her. Another dress Selena wore, which had originally been made only for her, got so much press that the company behind it (she believes it was BCBG) decided to produce it for the masses.

“That dress made it to production just because of Selena. If she didn’t wear it, they wouldn’t probably produce it,” she said.

The question of how long the hype will last is perhaps the most difficult to answer. Richard believes things will quiet down the moment the next “big, amazing thing happens.” Arnstein is a bit more optimistic, arguing that the hype will last well through the royal couple’s wedding and beyond. In fact, he sees it as a complete game-changer for the engagement market.

“This is the biggest wedding coverage in the history of world… [Middleton’s] going to be wearing this ring everywhere she goes. She’s going to be photographed in it hundreds and thousands of times. It’s going to be ingrained in people’s minds,” he said. “When people think ‘engagement ring’ they’re not just going to be thinking ‘diamond’ anymore.”

Whether or not Arnstein is wearing sapphire-colored glasses remains to be seen.