Diamonds: Stone sober

When you were a kid, your dad probably gave you pointers on how to buy a car. Too bad he didn’t teach you how to buy a diamond as well. An engagement ring can cost more than your first car, so knowing your way around a jewelry store can save you thousands of dollars. Here are six tips that will ensure you don’t get stuck with a lemon:

Forget about the silly guideline that says you should spend two-months’ salary on your fiancee’s rock.

That so-called rule was a marketing ploy developed by the diamond industry back in the 1940s to guilt guys into paying more than they could afford. If it puts your mind at ease, retailers say the average customer spends around $2,500 on a ring, which gets you between a quarter and half carat, depending on grading.

Diamonds are graded on criteria known as the four Cs: carat, cut, color and clarity.

Carat is the weight, cut is how well the diamond was shaped, color is how clear it is and clarity indicates the number of imperfections in the stone. Trouble is there are several grading systems out there, so it’s hard to compare a diamond at one store to another. “There’s a lot of abuse to this,” says Paul Lombardi, master gemologist at Birks & Mayors in Montreal.

Anyone operating below a millionaire’s budget should devote most of his attention to two of the four Cs — cut and color.

These are the two factors that have a direct impact on the amount of sparkle a ring gives off, which is how most non-experts judge a ring’s beauty. Buy a diamond with at least a “good” or “very good” cut grade from the GIA. Color refers to how much of a yellowish tinge is visible. Diamonds are graded from D to Z, with D being the best because it’s colorless. But an E or F diamond will do just fine, says Lombardi.

Save money by being choosy in the size of stone you buy.

Diamond prices spike at predetermined weights, such as a quarter carat, half a carat and one carat. Diamonds that are slightly smaller than those benchmarks are significantly cheaper. For example, a ring that’s 0.98 carats costs about $4,000 less than its one-carat equivalent (which goes fro $16,000). The difference in size isn’t noticeable.

Stick with round diamonds.

They never go out of style and they sparkle and glitter more than any other shape. A round diamond should have 58 facets, because that gives off the most sparkle, says Mo Charania, owner of Jubilee Fine Jewellers in Ottawa. Some jewelers claim their rings are better because they have up to 144 facets; don’t believe them.

Before you buy, take the ring out of the light.

Jewelry stores have bright lamps over their sales counters for a reason. Even an average diamond will glitter like a priceless gem in strong light. The correct way to judge a diamond is to look at it under indirect light. “If it’s a good diamond,” says Lombardi, “it will still have plenty of sparkle.”