In the Stone Age, Neolithic man prized gold for its luminous color and malleability. By the fifth millennium B.C., the Sumerians mined silver to create ornaments, jewelry and money. Later, the ancient Egyptians wore copper jewelry as a status symbol and to ward off evil spirits.

Now Tiffany & Co. is trumpeting that, in honor of its 175th anniversary, modern-day alchemists have made a new precious metal to adorn the wrists, fingers and necks of its wealthy clientele.

Trademarked as Rubedo (which means "red" in Latin), the pinkish mixture of gold, silver and copper has been fashioned into items priced at $200 for a slim pendant to $7,500 for a wide cuff, less expensive than the gold versions but more than the silver. The collection, Tiffany announced last month, is created from a "new jeweler's metal."

But metallurgists say there are two problems with those claims: Rubedo is not a metal, and it's not all that new.

"I Googled it trying to figure out what the heck it was," said John Barnard, director of the engineering science program at the University of Pittsburgh. "It seemed a little odd to me. I would never call it a new metal."

Rudolph Buchheit, chairman of materials science engineering at Ohio State, explained the difference.

"A new metal would be equivalent to creating a new element in the periodic table," he said. "It's what high-energy physicists do. It's not the thing you do in a jewelry foundry."

Alloys are commonly used by jewelers

What jewelers have used for millenniums are alloys, combinations of metals such as gold, silver and copper. White gold is an alloy of gold and white metals like silver, platinum and palladium. Yellow gold, the most common, is generally made with silver, copper and zinc. Rose gold, which gained popularity in the Victorian era and resembles Rubedo, gets its rosy hue from copper.

To the nonspecialist, objecting to the word "metal" might seem like quibbling. After all, plenty of familiar alloys such as steel, pewter and bronze are widely referred to as metals.

Carson Glover, the director of worldwide media relations at Tiffany, said a metal "is defined as an alloy of two or more metallic elements."

Besides, as Barnard said, as in love and war, "anything's fair in advertising."

But to many retailers, what's in a name is of crucial importance. For decades, Europe was bitterly divided over which heavenly concoctions had the right to be named chocolate. Until 2003, Spain and Italy banned candy makers in Britain and Denmark from labeling their products as chocolate because they added tiny amounts of vegetable fats instead of using only pure cocoa butter.

At the negotiations ending World War I, the French insisted that the Treaty of Versailles prohibit all grape growers outside the Champagne region from referring to their sparkling wine as Champagne. Cheesemakers outside Greece are forbidden by European law to use the word feta, because their product does not come from special breeds of sheep and goats.

Whether the formula for Rubedo deserves special status is impossible to say from a metallurgical viewpoint, said Anthony J. DeArdo, a professor in the department of mechanical engineering and materials at the University of Pittsburgh. He said it would be nearly impossible to prove that Rubedo is a unique mixture of metallic components, adding, "It may be one of the 14 million alloys that people have cooked up over the decades."

Certainly combinations of gold, silver and copper are not new, he said.

Analysis: Rubedo is more copper than gold

Although consumers generally don't know precisely what metallic ingredients are in their jewelry, the engraved karat sign K is recognized as a guarantee of the gold content. For instance, 14 karat is 58.5 percent pure gold; 18 karat is 75 percent.

Many Rubedo trinkets, which are being sold this year only, are imprinted with the signature of Charles Lewis Tiffany and 1837, the year he founded the store, but K is a mystery that bothers some jewelers.

"We really value the hallmark because it indicates the purity of the metal," said Christina Malle, a goldsmith. "In this case, there's no information that indicates any degree of consistency. Is it 9 percent or 1 percent gold? How do we know? It's confusing to the consumer."

Not so to a fluorescent X-ray spectrometer, a machine able to detect the presence of various metals in a material. An element analysis conducted by Goldbuyers.com, a gold refinery in New York City, found that Rubedo was about 31 percent gold and nearly 55 percent copper, along with silver and a smidgen of zinc. In karats, that comes out to about 7.5.

Donna Distefano Thomas, a jeweler in New York City who makes custom alloys, was not impressed.

"I think of it as a glorified copper or bronze, and a very clever marketing piece," she said.

Other jewelers were more complimentary.

"We think Tiffany's Rubedo, which evokes the warmth and sensuousness of rose gold, is a great trend and shows that we are coming full circle from the metal's prime in the Victorian era," said Tamar Kelman, who, with her partner Arik Kastan, uses 14-karat rose gold to make jewelry.

Tiffany was a marketing genius from the start

Tiffany, which expects sales to rise about 10 percent this year, hasn't been reluctant to brag about its marketing coups. The company's website relates how Tiffany, after buying the diamonds of French aristocrats fleeing political turmoil in the 1840s, "masterminded a second publicity coup in 1858" when the Atlantic telegraph cable was being laid. He bought 20 miles of extra cable, cut it into 4-inch pieces and finished them with brass. When they went on sale, the police had to be called in to control the crowds of eager consumers.

Glover of Tiffany's said, "When Tiffany began planning our 175th anniversary, we felt the development and introduction of a new metal would be a fantastic way to mark this momentous milestone while at the same time responding to our customers' desire for more blush-colored metals."

He added, "Customers are responding positively to this new metal."

Shoppers at the glass Rubedo counter at Tiffany's Fifth Avenue flagship store in New York City today are drawn in by the jeweler's classic styling and name as much as by the treasured metals and gems. With Charles Lewis Tiffany's signature on most of the limited edition Rubedo, that's exactly what they're getting.