The Details of Diamonds

By Kelly Marshall

If you're in the market for an engagement or wedding ring, you'll find a mind-boggling menagerie of jewel-related terms all around you—the "Four Cs," inclusions, princess cut, certificates—it's enough to make your head spin. Here then, in surprising simplicity, are the basics you need to know before you make what may be one of the bigger purchases in your life.

Diamond Trinket
More than two-thirds of the diamond rings sold in the U.S. are round-cut diamonds. The second most popular shape is marquise, and the others, in no particular order, are pear, heart, oval, emerald, and princess cut.

The 4 Cs    to top

When it comes to diamonds, each of the four Cs—cut, color, clarity, and carat (weight)—has its own importance when considering which stone is for you. Together, however, these four basic factors combine to distinguish the value and rarity of one diamond from another when you're comparison shopping. For instance, did you know that a larger diamond with a yellow undertone might be less valuable than a smaller, more colorless one? Let's explore each of these factors and the values to consider when making a diamond ring purchase.

The Cut    to top

The cut of a diamond refers not to the shape of a diamond, but rather the way a diamond is cut to reflect the maximum amount of light, or brilliance. A masterfully cut diamond with perfectly symmetrical cuts creates a magical sparkle by allowing the most light to enter and reflect back out of the stone. Likewise, a diamond can be ruined if an unskilled diamond cutter makes cuts either too shallow or too deep, thereby diminishing the amount of light reflected. The American Gem Society Diamond Grading Scale grades diamonds from the best—a rare ideal cut with a score of O, to the worst—the most inferior cut with a score of 10. It's important to consider the cut of the diamond when you're looking, but remember that a variety of other factors should apply before you make your decision. A less than perfectly cut stone can still be gorgeous in your eyes. As you'll likely discover, unless money is no object, that you'll be considering different cuts of diamonds and comparing the importance of this feature in relation to the other factors, such as clarity, color, and size, when making your decision.

Diamond Trinket
It's true—diamonds can cut glass, and just about anything else you can think of, including steel. In fact, the only mineral that can cut a diamond is a diamond itself.

The Color    to top

Did you know that diamonds come in a variety of colors? While most diamonds appear colorless, or with slight yellow or brown undertones, you can also have a diamond in pink, purple, green, black, blue, or the rarest of the "fancy" diamonds—red.

Generally, the more colorless a diamond, the more beautiful and valuable it is considered. Different organizations rank diamond colors differently, but here's how two societies—the Gemological Institute of America (GIA) using letters, and the American Gem Society (AGS) using numbers, ranks stones:









Near Colorless



Faint Yellow



Very Light Yellow



Light Yellow



Despite the elaborate ranking systems described here, it's difficult for an untrained eye to determine the subtleties in color. However, most reputable jewelers will have a set of Masterstones (a set of real diamonds displaying the full diamond color range) in the store, to help you see the differences. This is another area where the subtleties in color may be so faint that you're willing to opt for a more colored stone in exchange for a better cut, or a larger one. Let's examine the last two of the four Cs, and perhaps you'll have a better idea of which factors are more important to you personally.

The Clarity    to top

The clarity of a diamond refers to the number, size, location, and nature of tiny inclusions—natural impurities, such as traces of minerals, gasses, or other elements—found inside the stone. All but the rarest of diamonds has inclusions, making those that don't the most pure and valued stones. Yet, many stones contain inclusions that are not visible to the naked eye, so diamonds with inclusions shouldn't be avoided. In fact, since no two diamonds are alike, inclusions can act as tiny birthmarks that help identify one diamond from another under magnification.

Still, the clarity of a stone is a factor to consider when making your purchase decision. Both the GIA and AGS offer unique rankings in determining the clarity of a diamond. Visit their respective Web sites at or to find out more information.

The Carat    to top

Does size really matter? In the case of a diamond, it depends. Tradition seems to indicate that when it comes to an engagement or wedding ring on your finger, the answer is a resounding "yes." In fact, larger diamonds are rarer, so a larger diamond is often (but not always) more valuable. Again, the total value and rarity of a diamond is comprised of all four factors discussed here—cut, color, clarity, and carat weight.

Diamond Trinket
A diamond's weight is measured in carats, with one carat divided into 100 "points." Since the average size of a diamond engagement ring sold in the U.S. is 75 points, that means it weighs .75 carats.

Jewelers usually measure carat weights in _ carat increments, and most jewelers offer stones from _ or _ a carat to several carats in size. It's interesting to note that a "_ carat diamond" might actually weigh 23, 24, or even 26 points, when actually weighed. Reputable jewelers often carry scales that can measure down to .002 of a carat, so ask your jeweler to show you how they determined the weight of the stone you're considering.

As you can see, many factors go into the purchase decision of buying an engagement or wedding ring. Unless money is no object, you'll likely be considering all four factors and the trade-offs of size versus quality or quality versus size.

Diamond Trinket
While you're considering your diamond choices between cut, color, clarity, and carat weight, check out the completely customizable diamond-pricing tool online at You can select your preferences among the Four C's to get an idea of what you should expect to pay for different feature combinations.

So, we've covered the Four Cs, you've decided what's important to you, and you're ready to shop. But one question remains: How will you know what you're really getting at the jewelry store? Luckily, these days, any reputable jeweler should provide you with a certificate stating the authenticity of the diamond, including its quality, weight, and the cut of the stone. These certificates are produced by independent and objective labs that evaluate stones, rather than sell them. If your jeweler cannot provide you with a certificate for the stone you're considering, it's probably advisable to consider a purchase elsewhere. After all, if you're going to spend "two months' salary" on a ring that will last (okay?) a lifetime, this is one area where you want to make sure you get what you pay for.

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