Thinking of buying an engagement ring? A diamond bracelet? Diamond earrings?

Buying a diamond is a major purchase, so it pays to know what to ask and how to evaluate your purchase. Before you buy, there are a few things you should know about diamonds and their value.

We know: Seven Facts About Buying a Diamond

Here are five things to ask the jeweler or seller of the diamond you are considering purchasing, and two lesser-known tips. These aspects of the diamond are important to both its value and its beauty. ASK YOUR JEWELER TO TELL YOU ABOUT THE FOLLOWING:

CARAT

Carat is the measure of a diamond’s weight. One carat equals .2 grams or 200 milligrams. The greater the number of carats, the more valuable the diamond. The price of a diamond goes up exponentially in relation to its weight.

CUT

The cut of the diamond refers to the stones reflective qualities, not its shape. The cut determines the diamond’s brilliance or brightness. In general, the cut can be Ideal, Premium, Very Good, Good, Fair and Poor.

CLARITY

The clearer the diamond, the greater its brilliance and the greater its value. Many diamonds have “inclusions” such as scratches, blemishes, air bubbles and non-diamond material. Clarity categories range from diamonds without any flaws (flawless) to those that have blemishes only visible with a magnifying glass, to those that have blemishes that are visible to the eye. In general, you want to avoid the last category.

COLOR

The most valuable diamonds are colorless. They allow the most light to pass through the stone and create the most brilliance. Only a few diamonds are colorless, so most diamonds will have some yellow in them. The less yellow, the better. The color scale goes from A to Z: A diamonds are truly colorless (though no "A" or "B" diamond has yet been found) and Z diamonds have the most yellow or other color.

The value of a diamond is determined by taking into account each of these categories.

WHAT’S A DIAMOND CERTIFICATE?

A diamond certificate describes the quality of a particular diamond, including its weight and cut. (In contrast to an appraisal, which places a value on the diamond.) The two biggest labs that certify diamonds are the Gemological Institute of America (GIA) and the American Gem Society (AGS).

It’s a good idea to see if the diamond you want to buy is certified and ask to see the certificate.

DEBEERS and 'CONFLICT DIAMONDS'

If you specifically do not want to buy a Debeers diamond or other conflict stone (due to social and ethical issues), you don't necessarily have to! Ask your jeweler for the record of the source of the diamond(s) and make your purchase accordingly. Higher-volume jewelers may not have access to this information as they buy from many different sources, but it doesn't hurt to ask. Some retailers, such as Blue Nile, specifically carry "non-conflict" stones, and have dependable access to Canadian stones as well, which carry a higher price.

Did you know that 90% of all diamonds mined come from Africa, and 50% of the world's market is controlled by DeBeers? The decision you make is up to you, but it may be worth your time to do your own research and decide whether or not you would rather 'stay away' from these controversial stones.

VIEWING A DIAMOND AT THE STORE

When you ask a jeweler to let you look at a stone up close, they may set it on a black paper or cloth. Don't follow along! This is a tactic to make the stone look more brilliant than it may be. Insist on a white background when viewing a stone - it will reflect its true qualities. This is also a way to gauge the honesty of your jeweler - it's likely that a jeweler who gives you the stone on a white background to start is playing fewer games than one who doesn't.