Recently my unattached friend Katie told me that she had taken a trip to Tiffany's, solo, to try on diamond engagement rings. I shot her a look. "But they're just so sparkly!" she protested, deeply in lust.

Before another friend's bachelorette party, doing fact-?nding for the old "How Well Do You Know Each Other?" game, I asked her groom-to-be what was the best gift he’d ever given her. "The rock, of course," he replied instantly.

Later on, his ?ancée's answer lined up neatly: "That’s gotta be my ring!" she shouted to a limo full of hooting, nodding female heads, most of them attached to clapping hands adorned with dazzlers much like her own.

And then there's the hard-charging entrepreneur who, in an enviably ballsy move, spontaneously proposed to her ?ancé with a rock that she picked up on a nature hike in Minnesota. He accepted, but her ?nger is still bare because "we just haven't had time to shop."

"At ?rst, I was thinking we should ?nd something a little more egalitarian," she con?ded. "But then I thought, 'F--- it. I want a great ring.'"

And that pretty much sums it up, doesn't it? It would be a different story if the culturally mandated token of lifelong commitment was, say, a hood ornament on a chain, or something equally large and obnoxious, like those Pampers-box bathroom passes favored by smart-ass teachers in junior high school. But as things stand, there's no downside: The diamond engagement ring is a perfect con?uence of show-stopping sign and deeply emotional signi?er.

According to a recent DeBeers study, four out of ?ve brides receive diamond engagement rings. National Jeweler’s 2003 survey found that more than 40 percent of customers planned on buying a diamond one carat or larger. And the 2002 American Wedding Study (sponsored by Condé Nast) revealed that the average engagement ring costs $3,576: more than 16 percent of the average wedding budget.

No one can deny that we're in a "wedding moment" right now—and an expensive one, to boot. But the "timeless" symbol that kicks off many a frenzy of chocolate fondue fountains and sushi stations and ice sculptures is actually a fairly new development in wedding-paraphernalia history.

"It's hard to talk about exactly when these traditions started," says Vicki Howard, adjunct professor of economics and women's studies at Hartwick College. "Before the 1870s, diamonds were rare. People were wearing diamond engagement rings, but it wasn't yet a mass thing. In the late 1800s, archival evidence and etiquette books suggest, a wide variety of engagement and wedding band styles, including different stones, were considered proper and desirable."