Shape is a matter of preference and has less bearing on the value of the diamond than other characteristics. The diamond cutter determines the final shape of a diamond while the diamond is in the rough material state. The cutter’s primary objective is to maximize the finished product’s carat weight and proportioning while minimizing waste.

The cut of a diamond primarily refers to the diamond’s proportions and the quality of craftsmanship pertaining to the facets of the diamond. Facets are the flat edges of the diamond intended to draw light into the stone. When the proper proportions are used during the cutting process, light reflects out of the table (the top of your diamond). If the diamond is cut too shallow, you will see very little sparkle as light will simply be lost out of the bottom of the stone.
Likewise if the diamond is cut too deep the light will simply vanish out of the sides. The better the diamond’s cut, the more brilliant the diamond will also be when viewing the stone from the top down.

The most perfectly cut round diamond is called the “ideal cut”. Less than 2% of the world’s faceted round diamonds can be classified as ideal cut. Diamonds that are not ideal cut will lose some light through the bottom or sides of the stone. Many diamonds are intentionally cut with less than ideal proportions for the purpose of maximizing carat weight or to give the diamond a larger appearance.

For white diamonds, color grades indicate the lack of color. Color is widely considered the second most important characteristic after cut, as the color grading scale determines the whiteness of your diamond. How high a diamond will be graded on the scale will be decided by the least amount of color in the stone. Completely colorless diamonds are at the top of the color grading scale as D, E or F. These are the rarest and most expensive color grades.

When moving down the color scale to G, H and I, diamonds will begin to manifest extremely slight nuances of yellow, which typically cannot be detected by the untrained eye. Further down the scale, diamonds begin to reveal more color.

Of the Four Cs, clarity is the easiest to understand and grade, and leading experts believe that clarity generally bears the least impact on a diamond's appearance. Clarity refers to the naturally occurring inclusions inside the stone, these are also known as the diamond’s “finger prints”. As inclusions tend to be minuscule, they do not in most cases affect the beauty of a diamond in a noticeable way. Inclusions can appear as white spots or black carbon deposits which formed inside the stone during the crystallization process. Other inclusions can occur as tiny cracks, feathers and other internal vein-like characteristics. Diamonds that have the least amount of inclusions will be given the highest clarity grades.

The clarity grading scale begins at the top with Flawless, also known as F. Flawless diamonds possess zero blemishes both on the exterior and interior of the stone. These are the most rare and expensive of the clarity grades.

F, on the clarity scale, is followed by Internally Flawless, or IF. An internally flawless diamond has no interior inclusions, but may possess one or more exterior imperfections. Internally flawless diamonds are also extremely rare and valuable.

Following IF is VVS, or Very Very Slightly Included. VVS is split into two categories, VVS1 and VVS2, the latter having marginally more inclusions than the first. After VVS is VS, or Very Slightly included. VS also has two sub-grades, VS1 and VS2. VS is followed by SI, or Slightly Included, which has three sub-grades, SI1, SI2 and SI3.

Inclusions in the VVS, VS and SI grades are not visible to the naked eye and can generally only be viewed under intense magnification by a trained professional. Following SI on the clarity scale are I, for included, and C, which are commercial quality diamonds.

Carat refers to the weight of the stone, but does not wholly encompass the actual size of the diamond. Diamond size should be measured by 1) The carat weight, 2) The proportioning of the diamond and 3) The cut grading. For example, a diamond that is one carat in weight but is proportionally smaller across the top of the stone with a poor cut grading can appear significantly smaller than an ideal cut one carat diamond. If a diamond is cut using the correct proportions a diamond of a lower carat weight, but higher cut grade can appear considerably larger than a stone with a larger carat weight with a lower cut grading.

A single carat is comprised of 100 points. So 1/2 of a carat equals 50 points. The higher the carat weight, the rarer, and generally, the more expensive the diamond will be. Diamonds can range from 1 point to 545 carats, which is the largest known cut diamond on record today called the Golden Jubilee.

The price of a diamond goes up exponentially once it reaches the full- and half-carat weight benchmarks, whereas stones with a carat weight just under the round numbers of 1 Carat, 2 Carats, 2.5 Carats and so forth, can often reflect a lower price.