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They say that diamonds are a girl’s best friend. Never mind that the saying is gender-biased: It’s still true. You see it in the joyful tears shed during an engagement proposal, and in the glow that blossoms after opening the tiniest box under the Christmas tree.

But the perfect diamond requires no small investment, and if you think a halo setting has something to do with video games, you probably need to invest some time learning the basics before opening your wallet. Northshore spoke with Richard B. Berberian of Elyse Fine Jewelers in Reading, Steven Leed and Giao Nguyen of Royal Jewelers in Andover, and Michael Molloy of DeScenza Diamonds in Peabody to grasp the ins and outs of the Four C’s, how to balance budget against quality, the pitfalls of buying diamonds online, and much more. And whether you’re looking for something like your grandmother’s unassuming heirlooms or a blinding rock worthy of the red carpet, when it comes to diamonds, a little wisdom goes a long way.


Cutting a diamond transforms a rough chunk of concentrated carbon into a ring-ready gem,and the cut—the first of the Four C’s—determines a diamond’s sparkle and brilliance. “In gemological terms, cut grade refers to the proportions and geometry of the diamond,” says Berberian. A diamond is graded on a five-category scale ranging from “excellent” to “poor;” a poor diamond looks dull and milky, while an excellent diamond sparkles and shimmers whenever it moves under light.


Color, paradoxically, usually refers to the absence of color. The Gemological Institute of America (GIA) grades diamonds on an alphabetical scale running from D to Z, where diamonds graded D through F are white, bright, and desirable, while Z-rated diamonds are light yellow or brown castoffs. Generally, price drops dramatically as you move along the scale. (One important caveat: diamonds colored in shades like pink, blue, and orange are graded on a separate scale that gauges hue, tone, and saturation.)


Clarity refers to the existence of inclusions and blemishes on the inside or outside of the diamond—vestiges of when they were formed in the earth’s mantle aeons ago. Graded under 10x magnification, diamonds range on an 11-tier scale from flawless to very slightly included (VVS1-VVS2), very slightly included (VS1-VS2), slightly included (SI1-SI2), and included (I1-I3). Flawless diamonds are as expensive as they are rare—rare enough that plenty of jewelers have never seen one.


Carat weight—the last of the Four C’s, and a different measure from the karats that measure the purity of gold—gauges the heft of a diamond. One carat (1 CT) equals 200 milligrams. Higher numbers mean larger stones and potentially larger costs, but carats aren’t the be-all-end-all metric they’re sometimes cracked up to be. “You could have three stones that all weigh a carat, but all are going to look very different,” says Molloy.


Because no two diamonds are the same, Nguyen proposes an addendum to the Four C’s: combination. “You don’t want to concentrate too much on one aspect or sacrifice too much of another: You want to look at it as a balance,” says the Royal Jewelers executive vice president. That means looking past benchmarks for the so-called “best” color, clarity, cut, and carat weight you might find through Google searches and judging each diamond on an individual, holistic basis.


Buying a diamond without going broke requires compromises, but these four jewelers all stress the same thing: never sacrifice cut quality. “Cut is most important,” Nguyen says. “That’s what creates the sparkle factor, and that’s the first thing people notice.” By contrast, diminished clarity can lead to cost savings without affecting appearance: A diamond whose inclusions are only visible under magnification could look the same as a higher-graded counterpart. “To the naked eye, it’s not going to look any different, but it’s going to bring down the price considerably,” Molloy says. Additionally, a ring setting can help obscure imperfections, like those on the edge or underside of the diamond, Berberian says.


Halo settings (a large center stone surrounded with smaller diamonds) and pave? settings (small diamonds placed close together, creating the appearance of an unbroken diamond surface) have become two of the hottest styles in recent years, while the round brilliant cut shape remains as popular as ever. No matter what year it is, keeping up with the Joneses is always in fashion: Most spouses-to-be seek stones at least as large as the ones their betrothed friends are wearing, Leed says. “It’s not really a matter of one-upmanship—it’s more a matter of parity.” Fortunately, that old maxim of spending two to three months’ salary on a ring is out of vogue. These jewelers agree: Spend what you can afford, and get something nice.


Along with the qualities of the jewelry itself, the right diamond should sync with the wearer’s personality: A modest stone housed in a solitaire setting might match a traditional personality, while a mini-Kardashian might pick a small mountain at the center of a halo arrangement. To help figure out the best fit, most clients share as much information about the intended wearer as they can, and photographs can be a source of practical details: Berberian factors the shape of the wearer’s hand as well as their skin tone against the proportions and color of the diamond and metal used to fabricate the jewelry. Occupation and lifestyle matter, too—a diamond set in a ring worn by a nurse might have a lower profile than one worn by a desk jockey. And sometimes there’s room for whimsy: Berberian recalls a fiance?e having the inside of her groom’s ring engraved with the words, “If you’re reading this, you’re in big trouble!”


Considering that diamonds could rank among the most expensive purchases you’ll ever make, be cautious before handing over your credit card. Confirm your jeweler’s background and credentials, and make sure the GIA—the independent nonprofit organization that established the Four C’s and sets global standards for diamond grading—has certified the diamond. (Any other organization’s certification is basically meaningless.) Look at the stone loose, out of its setting, to see all of its imperfections. Be wary about shopping the Internet: Advertisements for $500 one-carat diamonds are usually low-quality, commercial-grade stones not up to snuff to be set in a ring, Molloy says. If you do purchase online, make sure an independent appraiser corroborates the quality of the diamond. And, Berberian says, “If you buy a diamond sight unseen on the Internet, you’re out of your mind.”


After you’ve chosen your diamond, think about how you plan to present it to your loved one, particularly if it’s an engagement ring. Instead of a proposal in a white-tablecloth restaurant, think of a more creative approach, like Nguyen’s client who orchestrated a Yankee Swap that ended with a fiance?e holding the box with a ring from her groom. Whatever you do, Leed says, don’t show the diamond to anyone else before you present it. (“There’s nothing worse than her having it on her finger and everybody says, ‘Oh yeah, I’ve already seen it.’”) And be prepared to scrap your plans on a moment’s notice—like when a suitor’s girlfriend accidentally walked into Royal Jewelers while he was sizing up her engagement ring. “He picked a ring, proposed on the spot, and we opened a bottle of champagne and celebrated,” Nguyen says. So besides following the Four C’s and the rest of the advice here, put some Moe?t on ice—just in case.