When shopping for diamond jewelry, considerations of cut, color, clarity and carat weight known as the "4C's" will guide you to a diamonds quality and value.
The 4 C's
More than any other quality, cut determines the fire and brilliance of a diamond. In order to maximize this fire and brilliance, the diamond cutter must place each of the stone's facets and angles in exact geometric relation to one another. On a classic round brilliant-cut diamond, for instance, fifty-seven or fifty-eight facets must be precisely aligned.
Diamonds come in many colors, but the overwhelming majority sold in the jewelry industry range from near colorless to very light yellow or brown. There are even colors called "Fancy colors" such as pinks, blue, yellow, reds and even greens.
The best color in today's market for a diamond (unless a fancy color) is the lack of color. It is the diamond that is totally colorless that allows white light to pass through it, dispersed as rainbows of color.
Most diamonds look colorless, but there are many subtle shade differences and the closer a diamond is to having no color the more valuable it becomes. D though G colors are the most valuable compared to N through Z colors, and the least desirable. During the diamond's formation, in the extreme heat and pressure, traces of elements such as nitrogen and boron could have been incorporated into the diamond's structure. It is these traces that give color or lack of it. The following chart shows the color grading groups broken out by definitions:
Most diamonds contain tiny identifying marks called "inclusions". The fewer and smaller the inclusions, the less likely they will interfere with the stone's beauty. Like a finger print, every diamond is unique. This could be due to minute traces of other minerals trapped in the diamonds during its formation. The number, color, nature, size and position of any inclusion determines the clarity of a diamond.
The fewer the inclusions, the rare it will be graded, and the more light it will reflect, thus making it more valuable. It is rare to find a diamond that has no inclusions, the closer to flawless the diamond is the greater the value. IF through SI encompass 50% of all gem-quality diamonds. The following chart shows the abbreviations and the definitions:
4. Carat Weight
A diamond's weight is the easiest of its characteristics to measure. The word "carat" originates from a natural unit of weight, namely the seed of the "carob" tree. The pods of the carob, or locust tree, contain seeds which are remarkably consistent in weight. These carob seeds were used by the early gem traders to weight their diamonds. Today, the system has been standardized and one carat was fixed at one-fifth of a gram.
A 1 carat diamond used to equal the weight of a carob seed, but today the carat is a metric weight of 0.2 grams, or 1/42 of a standard ounce. Each carat is divided into 100 points.
Example: a quarter carat = 25 points, written 0.25 Ct.
*Bonus: Different Shapes to Consider
In addition to the traditional brilliant round, diamonds come in a number of shapes. Some of the most popular are: Pear, Princess, Heart, Marquise, Emerald and Oval, just to name a few.