Although your budget and personal taste will have the most influence in determining
your final purchase, you must understand the 4 C's before you buy your diamond.
All of the characteristics below have influence on the value of the diamond.
The combination of these characteristics will affect and determine the cost of
your diamond. When you are ready to make your purchase, see a reliable jeweler.
Make sure the jeweler you choose is established with a good reputation.

SHAPE - Many people confuse cut with the shape of a diamond. The shape you select is a matter of individual taste. Diamonds can be cut into several different shapes. The most popular are brilliant (round), marquise, princess (square), pear, emerald, oval and heart shaped. The important issue is how well the diamond is cut into that particular shape.

TABLE AND DEPTH - Table and Depth percentage are two extremely important measurements for diamonds. The angles of cut will affect the diamond's ability to both reflect and refract light. If a diamond is cut too deep, light will leak out the sides. In this case, brilliance will be lost and the center of the diamond will appear to be dark. If a diamond is cut too shallow, light will leak out the bottom. In this case, the diamond will appear to be watery, glassy and dark. If a diamond has good proportions, the sides and bottom of the diamond will reflect light back to the top of the diamond.

SCINTILLATION AND DISPERSION - Scintillation is the alternating flash of white light and dispersion is the break up of white light into spectral colors.

POLISH AND SYMMETRY - Polish measures the quality of finish on the facets. Symmetry refers to the proper alignment of the diamond's sections, the proper shape for the cut, and the uniformity in size and angles of similar facets.

GIRDLE AND CULET - Girdle is the spacing between the upper and lower portions of the diamond. Girdles can be graded from "extremely thin" to "extremely thick". Extreme gradings should be avoided. The girdle finish can be natural, polished or faceted. The more expensive diamonds will usually have faceted girdles. The culet size refers to the smallest polished facet at the very bottom of the diamond. Chipped or large culets should be avoided.

COLOR: Diamonds vary in color from colorless to light yellow. Colorless diamonds are the most rare and the most valuable. The scale below represents the GIA (Gemological Institute of America) color rating system. The "D" to "J" ratings are the most desirable.

CLARITY: Almost all diamonds contain naturally occurring internal characteristics called inclusions. If a diamond is virtually free of inclusions and surface markings, it will be graded as flawless. These diamonds are extremely rare and very expensive. The size, location and number of inclusions will determine a diamond's clarity rating. Clarity ratings are determined by an expert gemologist under 10x magnification. The less inclusions there are, the more expensive your diamond will be. Inclusions that are visible to the naked eye will normally be graded as an "I".

FLUORESCENCE - Fluorescence can also naturally occur in diamonds. Cloudy fluorescence is undesirable. On the other hand, medium to strong blue fluorescence can be an asset to diamonds that are not in the colorless range, as it will tend to enhance the brilliance of the diamond and make it appear whiter.

CARAT-WEIGHT: The weight (and size) of a diamond is expressed in carats. One carat is divided into 100 points. Therefore, 25 points would equal a quarter of a carat or .25 carats. Many people think carat-weight is the primary determination, however, it is a combination of all the above characteristics that will ultimately determine the value of a diamond.

Reprinted from www.weddingzone.net