That said, even rank amateurs should familiarize themselves—before leaving home—with the famous "four C's" of diamond quality: cut, clarity, carats, and color. There's a debate among dealers about which C is most important. Some swear that cut is paramount; others that Americans think only about carat size. More moderate voices counsel that it's a combination of or, more realistically, a compromise among all four qualities that makes a diamond really special.
And then there are those two other important C's not in the official roster but arguably even more important than the original quartet. First, the "creepy" factor: virtually everyone I talk to in Antwerp emphasizes that even when the price is enticing and the stone seems luscious, if the dealer gives you a weird feeling in the pit of your stomach, walk out immediately. This brings us to the final C: chemistry—when you click with a dealer and know that he (alas, I didn't meet any female dealers) understands what you're looking for, whether that's a nine-carat door knocker or a pristine half-carat solitaire.
Joel Katz is just that kind of dealer. He has been active in the district for decades and helped create the Antwerp Diamond Jewellers Association (ADJA), which vets dealers and has strict membership criteria—to be eligible, you have to have been in the market for at least 10 years. I talk to Katz in his Appelmansstraat digs, a chic showroom with a massive marble fireplace and an imposing chandelier. "You must consider your jeweler as you would your doctor," he says, stressing the importance of trust between buyer and seller. "He is the expert!"
In the interest of improving my own expertise, I decide to visit Diamondland, an exhibition space and salesroom where the public can observe cutters and setters through windowed booths (though this reminds me a little of watching the animals at the famous Art Nouveau zoo a few blocks away). You can also buy here (it's an ADJA-approved venue), but the breathtaking floral brooch I fall for, with stones arrayed in the "invisible setting" popularized by the Parisian jeweler JAR, is a correspondingly stunning $39,500.
My next stop is the Diamond Museum, where at least I won't be tempted to spend a small fortune on a flower. Here, an exhaustive history of the trade is offered, and it's interesting, but I am more taken with the dark corridors that hold brightly lit cases filled with 19th-century regal diamond diadems, bravura tiaras, and other staggering works of art.
All this eye candy makes me want some actual sweets, so I stop in at the Del Rey tearoom, a haven of peace amid these bustling environs that has for more than a half-century served cognac-filled chocolates and pistachio marzipan to exhausted shoppers. My fellow patrons include three Middle Eastern women at the next table who are nearly silent, lost in thought (I'm pretty sure I know what they're thinking about), and a couple who are adding up a column of numbers and looking worried. Diamond-buying is a nerve-racking, if delicious, business.
With the museum's timeless ornaments living in my imagination, I decide to visit Salomon Wijnberg, whose antique-jewelry shop, Adelin, is just down the street from Dries Van Noten's fashion flagship. When it comes to vintage diamonds, it's not about mere size or glitter or color; it's the pure poetry of the setting, the history behind each facet, that makes a piece sing. Still, some things remain the same, whether a gem is burnished with age or brand-new.
"The only important thing is how you feel about it," Wijnberg says with disarming simplicity, showing me a mid-Victorian ring, marked $10,776, with a dazzling 1.7-carat center stone surrounded by two circles of smaller diamonds. I slip it on my finger and, as in a fairy tale, it's a perfect fit.
And it's every bit as beautiful, in its own way, as that impeccably proportioned dazzler on van Beurden's desk. As Wijnberg explains in detail about the period during which it was made and what arcane cutting techniques were employed, I can't help thinking back to something else Joel Katz told me: "Some people spend $20,000 or $30,000 on a diamond in 10 minutes, completely nonchalantly, while others sob uncontrollably over a $2,000 ring. It's not just about the jewelry, really—it's the whole experience. In the end, it's about falling in love."