How Diamonds are Graded and Valued
Information on diamond grades, colors, clarity and shapes and flawless diamonds.
Because no two gemstones are alike, sophisticated grading systems have been developed to measure a diamond's variable qualities. It is possible for a diamond expert to classify a single stone into one of 2,000 separate categories. The variable qualities of diamonds are grouped into four major categories, commonly referred to as the "Four C's": CARAT, COLOR, CLARITY, and CUT.
As a potential diamond owner, it is advisable to know what gives your diamond its unique value.
While minor variations in any of the following categories may affect the value of your diamond tremendously, all diamonds are subject to classification according to these four terms.
Cut refers to two things: the shape of the diamond and the proportions of the faceted stone. Diamonds may be cut in round, oval, marquise, pear shape, emerald or other exotic shapes. Historically, the round brilliant cut has been most in demand and has shown the greatest appreciation. The quality diamond is proportioned with mathematical precision. Any noticeable deviation from proper proportions will affect the diamond's brilliance, and hence its price.
The cut of a diamond will determine how light is refracted back out and this will determine the fire and brilliance of the stone. A well cut diamond refracts nearly all the light entering it out of the top (crown) and sides. This results in the form of greater fire and more brilliance.
2) Carat Weight
This adopted measure of weight calls for each carat to be subdivided into 100 "points" (By comparison, one carat equals l/5th of one gram, or 1/142 of one ounce.) All other characteristics being equal, the larger diamond will command the greater price. Diamonds are weighed with exact precision, using the metric carat system. While there is no guarantee that current trends will remain consistent, history dictates a faster appreciation for larger stones, and the greatest appreciation for those of the finest quality.
Diamonds are graded for color on a scale of "D" or colorless, to "Z" (Dark Yellow). While diamonds may be virtually any color, those with "white" or colorless features are most in demand and greater in value. The significance of a diamond's color on the stone's price is an important factor to consider. Just as history shows a higher appreciation for larger stones, it also shows the greatest appreciation for those in the higher color categories. Several grading systems exist, but the most accurate involves use of a reflectance spectrophotometer. This instrument eliminates opinion and is able to measure color with plus-or-minus 3 accuracy on a scale of 10.000 units.
Diamonds are graded according to their degree of clarity, with the finest referred to as "flawless": free of inclusions and imperfections when viewed through 10 x magnification. Diamonds which show very, very slight imperfections, detected through 10 x magnification, are designated as "VVS." Diamonds with minor inclusions are assigned "VS" or "SI" ratings. Finally, those diamonds with visible inclusions are assigned "Imperfect" ratings.