Shopping for the Perfect Diamond

You've probably already heard about the "4Cs," those famous universally accepted measurements of a diamond's value. Now all you need to decide is which are most important to you when choosing your gem.

Cut:

Often called the most critical of the four attributes of a diamond, cut refers its proportions. The more perfectly a craftsman has cut the diamond's shape, the more sparkle it will have.

Color:

"White" diamonds are graded on a scale from D (colorless and most pricey) to Z. Don't stress about this one; the untrained eye can't tell the difference from D to H. Simply ask if you can look at your diamond away from the store's bright lights to ensure you're happy with its color. (Colored diamonds are differently assessed. See "Color Code," at right.)

Carat:

This is a measure of your diamond's weight; one carat equals 200 milligrams. For a stone that's less than one carat, the weight will be measured in "points." Remember this: One carat equals 100 points, so a half-carat rock weighs in at 50 points, and so on. (Your stone's setting can make it look bigger. See "Set the Stage," below.)

Clarity:

When you look at your diamond through a magnifying loupe, you may see a tiny flaw—a whitish dot or dark spot that looks like a crystal or a cloud, for instance. Most of these "inclusions" can only be seen through a microscope, but the less there are in a diamond, the more flawless, rare and expensive it is.

For more on the 4Cs, go to gia.edu.

Set the Stage

Chic:

In a bezel setting, metal surrounds your gem, securing it with a rim. This setting can actually make your rock look bigger. Pay close attention to the metal's color—yellow or white gold, for example—to be sure it shows off the hue of your diamond. Ring by A. Jaffe.

Classic:

A prong setting like this one holds your diamond in place with metal claws. It's the most popular setting because it lets light in—and out—from all angles, creating brilliance. Be sure you love how the prongs look and the way the setting cradles your gem. Ring by Tiffany.

Modern:

An ultracontemporary tension setting holds the stone so it seems to hover in the middle. Don't worry; this rock isn't going anywhere. More than 65 pounds of pressure keep it firmly positioned, making it quite the conversation piece. Ring by GelinAbaci.

Color Code

Have you been eyeing the candy-hued carats worn by stars like Heidi Klum and Katie Holmes? Know that shopping for your own colored diamond presents some challenges.

“Only one out of ten-thousand diamonds is naturally colored,” says Jordan Fine of the Natural Colored Diamond Association (NCDIA). “You could have a hard time finding a large selection.”

Luckily, the NCDIA’s website (ncdia.com) lists retailers and designers who work with these coveted stones. Once you’re at the store, know that the 4Cs don’t exactly apply. “With a colored diamond, it really is about the color,” says Fine.

Gray, yellow and brown are more common than pink, blue and orange; the rarer the color, the pricier the stone. The intensity of your chosen hue is the other major factor. In general, pale shades are more affordable than deep ones. “A one-carat diamond in a vivid pink can cost ten times as much as one that’s pale,” says Fine.

And while that cost would range from $20,000 to $200,000, you don’t need a fortune to afford a colored rock. “Yellow, champagne, olive and cognac diamonds can cost about the same or even less than some white diamonds,” says Fine.