Whether you and he have discussed marriage or you just have a hunch that he may pop the question in the near future, you've probably given some thought to a diamond ring. If you and your intended shop for your diamond ring together, become familiar with the elements of diamond quality before you get to the mall. Invented by the Gemological Institute of America, the diamond grading system is commonly known as the "4 Cs" - carat, clarity, color and cut.

Carat

Carat weight measures a diamond's size. Each carat is equal to 100 points. Thus, a .75-carat diamond is the same as a 75-point stone or a 3/4-carat diamond. According to the Diamond Information Center, the larger a diamond, the more rare it is. Not only are larger diamonds found infrequently in nature, but they also show off the stone's color and cut to the best advantage.

Clarity

According to the Diamond Information Center, the purer a diamond, the more brilliant it is. A diamond's clarity is judged by the number, color, type, size and position of inclusions - "nature's birthmarks" - it contains. The fewer inclusions the stone has - as determined by a grading system - the more valuable it is.

Color

The purer the color of a diamond, the more rare it is. Truly colorless diamonds are the most valuable, while those with subtle yellow or brown tones - as determined by a grading system - are less so. Comparing stones side by side is the best way to see the color of each stone.

Cut

The Diamond Information Center maintains that, while nature is responsible for the other three Cs, it is the cut of a stone that releases its sparkle and beauty. When a diamond is cut to good proportions, light will reflect from one mirror-like facet to another and disperse through the top of the stone, resulting in a display of its brilliance.

There are several different shapes of cut diamonds; the one you choose depends upon your personal taste. Marquis cuts are out of style, but Princess, Round, Oval, and Emerald diamond rings are chosen by many couples.

While diamond rings have traditionally been comprised of a single diamond or solitaire, the current trend is a ring with a center stone and side diamonds. As for settings, there are over half-dozen categories to choose from. The prong setting is still the first choice for most buyers, but that the bezel setting is also popular. And, while yellow gold may make a comeback in the future, the hot metal for diamond rings is still platinum. While it's pricier, it's also heavier, hypoallergenic, and will never tarnish.