To celebrate, to commemorate, to reward, to romance - there are many reasons to buy a diamond. When making an investment in jewelry, especially diamonds, it is important to employ the 4 Cs: Color, Clarity, Cut and Carat weight to ensure value and appreciation. The Gemological Institute of America established the 4 Cs of diamond value to help diamond professionals describe and classify diamonds. When taken together, the 4 Cs help in evaluating a finished diamond.

Color

Many people think of diamonds as colorless, but in reality, truly colorless diamonds are quite rare. Most diamonds used in jewelry are nearly colorless with faint yellow or brown tints. Such nearly colorless diamonds fall in the normal color range and are graded by their relative lack of color. In fact, a diamond that is considered to have fine color has little or no visible coloration. The grading system ranges from color D, which indicates a rare colorless diamond, to color Z, with yellow characteristics.

Diamonds outside the normal color range are called fancy-colored and come in virtually any color imaginable. Red and green are the rarest fancy colors, followed by purple, violet, blue, orange and pink. Yellow and greenish-yellow diamonds are more common, but still considerably rarer than diamonds within the normal color range.

Clarity

Like color, clarity is a key factor in determining a diamonds value. Diamonds have internal features called inclusions, as well as surface irregularities, termed blemishes. Together, inclusions and blemishes are referred to as clarity characteristics. Clarity is the relative absence of clarity characteristics. Blemishes refer to the cuts or nicks on the outside of the diamond, while inclusions occur inside the diamond, such as mineral crystals trapped inside the diamond.

While some clarity characteristics may have a negative influence on diamond value, some can have a positive effect as well. Firstly, they help gemologists separate diamonds from lab-created diamond simulants. Secondly, because no two diamonds have exactly the same inclusions, they can help identify individual stones. And thirdly, they provide scientists with valuable information about how diamonds are formed.

Cut

Many think of cut as the shape and style of a polished diamond, but it also refers to a value factor - the proportions, symmetry and finish of a diamond, often called make in the diamond trade. A diamond with a good make is bright, fiery, symmetrical and sparkles with the light. There is more than one way of cutting a diamond to make the most of its optical properties. Cutting a diamond to produce the maximum return of light depends on the relationship between three critical proportions - table size, crown angle and pavilion depth. Jewelry makers can combine these in a variety of ways to yield equally bright round brilliant cut diamonds. Bottom line: a well-cut diamond will direct more light through the crown, or top of the diamond.

Carat Weight

The carat weight of a diamond has to do with the basic measuring unit of diamonds. One carat equals .200 grams (or 200 milligrams) Some weights are considered magic sizes - half carat, three-quarter carat. While visually theres little difference between a 0.99 carat diamond and one that weighs a full carat, the price differences between the two can be significant. The aspect of carat weight that surprises people is the relationship between rarity, weight and value. It is not always easy to understand why a 2-carat diamond might be worth more than twice as much as a 1-carat diamond of similar clarity, cut and color. The concept is pretty simple: Large diamonds are rarer than small diamonds. The scarcer a diamond is, the higher its worth. So a larger stone doesnt just cost more, it also costs more per carat.