By Ken Sweet, AP Business Writer

NEW YORK (AP) — The demand has been so overwhelming that the manufacturer ran out of raw material in just a few days. Enthusiasts extol its virtues all over the internet. Millennials are clamoring for it.

It's not a new video game, or some fancy food craze, or even Apple's latest iPhone, but a credit card.

Calling it plastic wouldn't do it justice. It is a high-end, high-fee, high-reward card made of a metallic alloy that gives it a satisfying heft and an impressive thunk when you toss it onto the table to pick up the check.

The Chase Sapphire Reserve Card has become the hottest card on the market just two weeks after being introduced, even though it came out during the slow, end-of-summer period, it carries a hefty $450 annual fee, and JPMorgan Chase spent nothing on advertising it.

"I'm telling all my friends about it," said Maddy Novich, 33, of New York, who applied for the card, as did her husband.

Like so many crazes these days, this one has been fueled by social media, word of mouth and the internet. Frequent travelers and those who try to game travel-loyalty programs have been writing extensively about the card on blogs and forums.

"I have never seen such interest in a credit card, and I've been doing this for 15 years," said Gary Leff, who runs the travel and points blog View from the Wing.

Chase has approved tens of thousands of applications for the card, said spokeswoman Lauren Francis. Most of the customers are millennials, who typically shun credit cards and are not usually a target for high-fee, ultra-premium plastic.

The demand has been so high that Chase ran out of the alloy, whose composition is a trade secret. Customers are being issued temporary plastic cards.

"We quickly ordered more, but because they are handcrafted, they take more time to make," said Lisa Walker, general manager of Chase's Sapphire credit card program.

Credit cards with high fees but generous rewards are aimed at well-to-do customers who spend and travel extensively. The market has long been dominated by American Express with its Platinum Card.

So why's the Chase card so hot?

Chase offers a 100,000-point sign-up bonus if the customer meets certain spending targets. Those points can be worth up to $1,500 in travel rewards. They can also be converted to hotel or airline points that could secure, oh, a dreamy hotel suite in the Maldives or a first-class ticket for, say, a honeymoon.

The card also comes with a $300 annual credit toward travel, which effectively makes the annual fee really $150. It has a generous points-earning program, with triple points on travel and dining, and gives access to airport lounges.

"It's one of the best offers I've ever seen. With the amount of travel and dining we do, I saw it as a worthwhile card to get," Novich said.

The card's metal composition is also clearly part of the appeal. Only a handful of other credit cards are metal, including the American Express Centurion Card, commonly known as the AmEx "black card," which is typically available only to millionaires, billionaires and celebrities.

Kayla Kania, a 33-year-old manager at an accounting firm from Rockville, Maryland, proudly posted a picture of her new Chase card on Instagram and said she has received compliments about it from cashiers and a co-worker.

"The metal part of it, people get excited about it. It's weird," she said. She added: "It's such a conversation piece."

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