Diamond quality chart for grading size, clarity and color
Diamond Grading Terminology
A diamond's value is based on the characteristics known as the "4 C's".
Carat is the unit of weight for all gemstones. One carat has 100 points like a dollar has one hundred pennies. Therefore a diamond measuring 50 points is 1/2 carat in weight, or 0.50ct. There are five carats in a gram. There are 31.5grams to a metric ounce. If you do the math, it would take quite a few 1ct stones to weigh an ounce.
A diamond's clarity is determined by the number, nature, position, size and color of internal characteristics called "inclusions" and surface features called "blemishes". These irregularities occurred in the liquid magna (volcanic rock) within which the diamond was created. Diamonds are mostly pure carbon, however, during crystallization other minerals nearby, or even other bits of carbon forming more quickly may have become trapped within the cooling mass. These show themselves as the various characteristics which make up the clarity of a diamond (included crystals, feathers, clouds etc). The clarity of a diamond is graded by using 10X magnification under good lighting by an experienced grader. Below are the clarity grades by GIA standards.
FL - FlawlessFree of all blemishes and inclusions
IF - Internally FlawlessNo inclusions visible, only minor blemishes.
VVS1 - Very Very Slightly Included 1Minute inclusions extremely difficult to locate.
VVS2 - Very Very Slightly Included 2Minute inclusions extremely difficult to locate.
VS1 - Very Slightly Included 1Minor inclusions difficult to locate.
VS2 - Very Slightly Included 2Minor inclusions somewhat easy to locate.
SI1 - Slightly Included 1Noticeable inclusions easy to locate.
SI2 - Slightly Included 2Noticeable inclusions very easy to locate.
I1 - ImperfectObvious inclusions usually easy to locate with the unaided eye.
I2 - ImperfectObvious inclusions easy to locate with the unaided eye.
I3 - ImperfectObvious inclusions very easy to locate with the unaided eye and affect the stones brilliance.
A diamond should have no color at all, which would give it a perfect "D" color. Every color after "D" would start to have the faintest signs of yellow or brown (most common diamond color) increasing to the end of the scale at "Z". Anything with more color than "Z" would be classified as a "fancy color", where the prices can become more expensive as in the D and E colors. A machine called the "Colorimeter" can be used for color grading but there is no substitute for the trained human eye.
The sometimes forgotten "C", ensures that a given stone has maximum brilliance and sparkle which would not be the case were the stone cut for weight alone. Simply put, when looking at a diamond, if it doesn't catch your eye or if it doesn't flash in the light, it's probably not well cut. Good cutting is essential to have a brilliant fiery stone.