Various characteristics of diamonds are graded and categorized by the diamond industry. To learn about diamonds is to first learn about the "four Cs" of diamonds -- the four characteristics which are considered the most important in determining a diamond's value.
These are the criteria jewelers use when grading diamonds, and they're the ones you'll need to understand to buy the right diamond for you.
Cut is probably the most important, and most challenging, of the four Cs to understand. The brilliance of a diamond depends heavily on its cut.
To determine the cut grade of the standard round brilliant diamond - the shape that dominates the majority of diamond jewelry – the GIA (Gemological Institute of America) calculates the proportions of those facets that influence the diamond's face-up appearance. These proportions allow the GIA to evaluate how successfully a diamond interacts with light to create desirable visual effects such as:
Brightness: Internal and external white light reflected from a diamond
Fire: The scattering of white light into all the colors of the rainbow
Scintillation: The amount of sparkle a diamond produces, and the pattern of light and dark areas caused by reflections within the diamond
The GIA's diamond cut grade also takes into account the design and craftsmanship of the diamond, including its weight relative to its diameter, its girdle thickness (which affects its durability), the symmetry of its facet arrangement, and the quality of polish on those facets.
The GIA Diamond Cut Scale for standard round brilliant diamonds in the D-to-Z diamond color range contains 5 grades ranging from Excellent to Poor.
Most diamonds contain some inner flaws, or inclusions, that occur during the formation process. The visibility, number and size of these inclusions determine what is called the clarity of a diamond. Diamonds that are clear create more brilliance, and thus are more highly prized, and priced.
Clarity actually refers to the absence of inclusions and blemishes in a diamond.
Natural diamonds are the result of carbon exposed to tremendous heat and pressure deep in the earth. This process can result in a variety of internal characteristics called 'inclusions' and external characteristics called 'blemishes.'
Evaluating diamond clarity involves determining the number, size, relief, nature, and position of these characteristics, as well as how these affect the overall appearance of the stone. While no diamond is perfectly pure, the closer it comes, the higher its value.
The GIA Diamond Clarity Scale has 6 categories, some of which are divided, for a total of 11 specific grades.
Flawless (FL) :
No inclusions and no blemishes visible under 10x magnification
Internally Flawless (IF):
No inclusions visible under 10x magnification
Very, Very Slightly Included (VVS1 and VVS2):
Inclusions so slight they are difficult for a skilled grader to see under 10x magnification
Very Slightly Included (VS1 and VS2):
Inclusions are observed with effort under 10x magnification, but can be characterized as minor
Slightly Included (SI1 and SI2):
Inclusions are noticeable under 10x magnification
Included (I1, I2, and I3):
Inclusions are obvious under 10x magnification which may affect transparency and brilliance
Many inclusions and blemishes are too tiny to be seen by anyone other than a trained diamond grader. To the naked eye, a VS1 and an SI2 diamond may look exactly the same, but these diamonds are quite different in terms of overall quality. This is why expert and accurate assessment of diamond clarity is extremely important.
Colorless diamonds are the most desirable since they allow the most refraction of light (sparkle). Off white diamonds absorb light, inhibiting brilliance.
Diamond color actually means "Lack of Color"
The diamond color evaluation of most gem-quality diamonds is based on the absence of color. A chemically pure and structurally perfect diamond has no hue, like a drop of pure water, and consequently, a higher value. The GIA's D-to-Z diamond color-grading system measures the degree of colorlessness by comparing a stone under controlled lighting and precise viewing conditions to masterstones stones of established color value.
The GIA's diamond D-to-Z color-grading scale is the industry's most widely accepted grading system. The scale begins with the letter D, representing colorless, and continues, with increasing presence of color, to the letter Z.
Many of these color distinctions are so subtle that they are invisible to the untrained eye; however, these distinctions make a very big difference in diamond quality and price.
A carat is the unit of weight by which a diamond is measured. Because large diamonds are found less commonly than small diamonds, the price of a diamond rises exponentially to its size.
Diamond carat weight is the measurement of how much a diamond weighs. A metric "carat" is defined as 200 milligrams.
Each carat can be subdivided into 100 "points". This allows very precise measurements to the hundredth decimal place. We would describe the weight of a diamond below one carat by its "points" alone. For instance, a diamond that weighs 0.25 carats would be described as a "twenty-five pointer". Diamond weights greater than one carat are expressed in carats and decimals. A 1.08 carat stone would be described as 'one point oh eight carats.'
All else being equal, diamond price increases with diamond carat weight, because larger diamonds are more rare and more desirable. But two diamonds of equal carat weight can have very different values (and prices) depending on three other factors of the diamond 4Cs: Clarity, Color, and Cut.
It's important to remember that a diamond's value is determined using all of the 4Cs, not just carat weight.
Additionally, there's one other characteristic of a diamond which makes it worth more: a certificate, or grading report.
This report, supplied by reputable organizations such as the Gemological Institute of America, is a complete evaluation of your diamond that has been performed by a qualified professional with the help of special tools. Every diamond has its own recognizable, individual characteristics, which are listed on the certificate.
For more information on these diamond characteristics, please contact us.