About Diamonds
Four factors that are considered when judging a diamond's quality and cost are: the diamond's color, its clarity, diamond cut, and carat weight. These four elements are known as the Four C's.
Color
Colorless diamonds are quite rare. Most diamonds used in jewelry are nearly colorless with faint yellow or brown tints. The less color, the higher the grade and the value. With mounted diamonds under a half carat, it's almost impossible for people with no gemological training to see any differences in the top five or six grades. But the differences are there and they can have a drmatic affect on price.
The GIA Color Grading Scale ranges from D to Z+. Grades D to Z are the normal range of colors. Grade Z+ come in just about any color you can imagine and are called fancy-colored.
| Grade |
Color |
| D, E, F |
Colorless |
| G, H, I, J |
Near Colorless |
| K, L, M |
Faint Yellow |
| N, O, P, Q, R |
Very Light Yellow |
|
S, T, U, V, W, X, Y, Z |
Light Yellow |
| Z+ |
Fancy |
Clarity
Almost all diamonds contain small amounts of non-crystalized carbon or other elements or tiny fractures called inclusions. They may also have surface irregularities called blemishes. Together, they are called clarity characteristics. Most are too small to be seen without magnification, but they can sometimes affect the transmission of light through the diamond, diminishing its brilliance. The term Diamond Clarity refers to the number of clarity characteristics and their effect on the diamond's transparency, if any. The Gemological Institute of America (GIA) has established a Diamond Clarity Ratio.
The chart below is based on the GIA diamond clarity grading system. All grading takes place under 10x magnification.
| Grade |
Meaning |
Definition |
| FL |
Flawless |
No inclusions or blemishes. |
| IF |
Internally Flawless |
No inclusions; slight external blemishes. |
| VVS1, VVS2 |
Very, Very Slightly Included |
Minute inclusions. Difficult for an experienced grader to detect. |
| VS1, VS2 |
Very Slightly Included |
Minute inclusions. Not easily seen by an experienced grader. |
| SI1, SI2 |
Slightly Included |
Inclusions that are noticeable to an experienced grader under 10x magnification. Not easily visible to the naked eye. |
| I1, I2 |
Included |
Inclusions that may affect transparency. If under 10 points, inclusions can not be seen by the naked eye.* |
| I3 |
Included |
Obvious inclusions that may affect transparency and brilliance. Imperfections may take away from the beauty of the stone. |
| * 10 points = 1/10 of a Carat |
Cut
The cut of a diamond — its roundness, depth and width, the polish and symmetry of the facets — all
determine a diamond's brilliance. Many gemologists consider the cut the
most important diamond characteristic because even if a diamond has perfect
color and clarity, a diamond with a poor cut will have dulled brilliance.
Carat Weight
Diamonds are measured in carat weight. One carat is equivalent
to 1/5 of a gram. Also, there are "100" points in a carat, so that a .50 "point" diamond
would be described as a half-carat.
In general, the pricing for polished diamonds is directly related to the pricing for the diamonds in their rough state. Because there is a scarcity of large diamonds in the rough, the price for these diamonds after polishing will be higher per carat. As you get larger in carat weight there will be an incremental jump in price even between two diamonds of same color and clarity. These plateaus are found approximately every .10-.15 points. Category examples are: .50-.59, .60-.69, .80-.89, .90-.99 carat, etc.
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