4Cs of Diamond Grading
A diamond grade can be broken down into 4 categories called the 4Cs. They are Cut, Color, Clarity, and Carat. These are the factors that you as a consumer should be aware of in order to make an educated buying decision.
The cut of a stone refers to it's make, or proportions , rather than it's shape . Proper proportions between the stone's table , crown , and pavilion along with strategically placed facets produce the vibrant display of color and light known as �fire� which is highly desirable.
The phenomenon of fire occurs when light enters through the crown of the diamond which acts as a window into the stone. The light then hits the pavilion area of the diamond where it is refracted and redirected back up through the crown of a diamond and Voila! You now have a dazzling display of shimmering light and color ready to take anybody's breath away.
If a stone is cut too shallow the light would not be directed properly back up through the crown and you would have a less lively diamond.
If a stone is cut too deep the light would dissipate and create a dark area around the center of the diamond.
So what proportions will produce an attractive stone?
- Depth Range: 57%-63%
- Table Range: 55%- 64%
Percentages are representative of comparisons with the width of the stone.
Diamonds are graded on a color scale from D to Z. D being a colorless diamond and Z being yellow or brown. In general, diamonds with grades D, E, and F are considered to be colorless and G through J to be near colorless according to G.I.A . standards.
Color is caused by the introduction of natural elements during the formation of the diamond other than carbon, which is the only element a diamond is composed of. Most commonly trace amounts of nitrogen will give a diamond a yellowish hue and boron will give it a bluish hue.
The less color a diamond has (whiter) the rarer it is and therefore more expensive it will be. Remember that a stone with less color (D) will not necessarily be more beautiful than a yellowed stone (M), just rarer. Beauty is in the eye of the beholder!
The Clarity grade is the measure of a diamond's inclusions (flaws) or lack thereof.
Several factors can contribute to a diamond having inclusions such as pressure, extreme heat, and cooling while a diamond is being formed or during a volcanic eruption, which brings a diamond up to the earths surface through a host stone called kimberlite.
These inclusions are normally either non-crystallized carbon or internal stress fractures. Using the industry standard 10x magnification lens, diamonds are classified into one of the following categories:
Flawless (F): The diamond is internally flawless and free of surface blemishes.
Internally Flawless (IF): The diamond is internally flawless.
Very Very Slightly Included (VVS1-VVS2):
These diamonds contain only the slightest, most minor of inclusions. Inclusions are not visible to the naked eye. Difficult to very difficult to detect under 10X magnification.
Very Slightly Included (VS1-VS2): These diamonds usually have either one inclusion near the table of the stone or more than one inclusion elsewhere on the stone. Possible minor surface scratch or other minor external defects. All inclusions are not visible to the naked eye. These inclusions are only visible under 10X magnification.
Slightly Included (SI1-SI2): Inclusions on these diamonds are easily detectable with a 10X magnification lens. The sharp, seasoned eye may be able to detect the inclusion(s) unaided by a 10X lens.
Included (I1-I2): Inclusions are visible to the naked eye.
Included (I3): These diamonds are heavily included and might look more like a piece of rock salt than a diamond. The stone is prone the chipping or breaking especially around the girdle. We refuse to sell this type of diamond. We don't want anybody making the mistake of buying this kind of stone just to pinch a few pennies.
Note: Some labs use an SI3 grade to classify stones that are borderline SI2-I1. The G.I.A. does not recognize SI3 as a diamond grade. 'I' stones are frequently referred to as 'pique'.
Carat is the unit used to measure the weight of a diamond, or any other gemstone for that matter. The word carat is derived from the carob. Before the advent of modern weight scales, carob seeds were used to determine the weight of a stone.
1.00 Carat (ct.) = 0.200g or 1/5 of a gram
The carat may also be divided into �points� or pt..
100pt. = 1ct.
Therefore a diamond the weighs 0.27ct may also be referred to as 27pt. or a 27 pointer.
Most people think of Carat as having to do with the size of the stone. If this is you, you are somewhat correct so don't feel too bad.
A properly cut diamond will yield a relative size per carat. For example, a 1.00ct. diamond will be exactly or around 6.5mm in diameter.
Also, the heavier the diamond the rarer it is and the more expensive it will be. For instance, the total cost of four O.25ct G VVS2 diamonds (time to put your new found knowledge to work) will not be as expensive as a 1.00ct G VVS2 diamond.