Diamond are one of the world’s most valued natural resources, not to mention one of the most highly desired gemstones. Diamond are naturally made with an enormous variety of characteristics, making each individual diamond unique. The many possible combinations of these characteristics determine the overall quality and value of a diamond. Recognizing the need for a universal grading system, GIA, the Gemological Institute of America, regarded as the world’s most respected institute of gemological research, developed the Four C’s. The Four C’s stand for Cut, Color, Clarity, and Carat Weight. This internationally accepted diamond grading system has revolutionized the diamond trade and today is used by nearly every professional in the industry and diamond enthusiasts across the globe. Because individual diamond vary so immensely in quality and price, it is vital for consumers to be familiar with the Four C’s as well. We’ve outlined the basics of this grading system below, to help give consumers the resources they need to make educated purchases.
The cut of a diamond may be one of the most important of the Four C’s, and can enhance the overall quality, value, and beauty of that diamond. There are many different cuts, each having a specific effect on the following three attributes:
* Brightness – the amount of light the diamond reflects
* Fire – the various colors of the spectrum that a diamond gives off
* Scintillation – the sparkle and brilliance that is produced when a diamond is moved
In a well cut diamond, the light which enters through the table (the top flat facet) and travels through to the pavilion is then reflected and dispersed through the crown, creating a desirable effect. Unfortunately, in a poorly cut diamond, some of the light leaks out the girdle, which dramatically reduces the diamond’s sparkle.
The quality of a diamond cut is based primarily on symmetry and polish, as well as the proportions of the table size, crown angle, and pavilion depth to one another. In most cases, the more facets a diamond has, the more brilliance and sparkle it will have. However the depth of the pavilion also has a huge impact on this. When the depth of the pavilion is either too much or not enough, the light can be lost out the sides of the stone instead of being directed through the crown.
The brilliant round cut diamond is by far the most common of the diamond cuts, although many others are gaining popularity. The brilliant round cut was designed specifically for use on diamond, and with it’s 57-58 well proportioned facets, it’s brilliance and sparkle is more noticeable than on most cuts. Yet with so many variations of diamond cuts, many combinations of proportions are possible, directly affecting the beauty of a diamond, and therefore also the value.
Similar to the cut of a diamond, it’s color will either increase or decrease it’s sparkle and fire. Obviously, diamond with less color will reflect more light than those with a light yellow or brown hue. This, along with the fact that nature provides us with less of these colorless diamond, makes them more valuable and sought after.
Once again seeing the need for a universal system, the GIA developed the diamond color grading scale, using the letters D-Z, which is most widely accepted today. Diamond are graded under very precise viewing conditions and often compared to diamond of a known color grade to ensure very few differences within a color grade. A diamond absent of color is grade ‘D’ and the more color that is present in the diamond, the further along the alphabet it’s grade travels. Diamond with grade ‘Z’ will have a light yellow or brown tint, and therefore will not reflect light as well as a colorless diamond. Fancy colored diamond, although most are irradiated and color enhanced, do not follow this grading scale, and often are more valuable because when naturally colored they are extremely rare.
The most common color grades are G through I, as they are more abundant in nature, and much more affordable. Although diamond of these grades do have a hint of color, it generally isn’t visible to the naked and untrained eye. Likewise, diamond graded J through M may have a very faint hue of yellow, but with the right jewelry piece and diamond cut, the color may look less obvious (although it barely is to begin with). White gold or platinum settings usually require higher grade diamond, whereas a yellow gold setting takes away from the yellow tint of a lower grade diamond.
Most jewelers use the GIA Diamond Color Grading Scale [out], and it’s recommended for customers to do the same to better understand the subtle differences in color a diamond may have, and to better assess the quality and value of a diamond.
According to the GIA, “diamond clarity refers to the absence of internal inclusions or external blemishes.” Of all diamond characteristics, clarity may be the one with the greatest impact on a diamond’s value, since flawless diamond are so rare. Natural diamond are created deep within the earth under extreme pressure, so it’s not surprising that nearly all diamond have minor flaws. There are two types of flaws – blemishes and inclusions. Blemishes are external flaws found on the surface of a diamond, and include chips, nicks, and scratches, most of which occur during the cutting process. Inclusions are internal flaws such as bubbles, cracks, or other minerals within the center of the diamond.
GIA developed a universal diamond clarity grading scale consisting of 11 grades. Diamond are graded under 10x magnification, so most of the flaws that affect the clarity grade are barely visible to the naked eye. In addition to the number, size, and severity of the inclusions, the position and color of the the inclusion are also considered when grading the clarity of a diamond. Since no two diamond are alike, the characteristics of a diamond and it’s inclusions make it entirely unique, and are sometimes used, like fingerprints, to identify individual diamond.
The most rare clarity grades are F or FL (flawless) and IF (internally flawless), diamond of these grades are much more valuable because they do not occur as often in nature. The next best clarity grades are VVS (very, very slightly included) and VS (very slightly included). These diamond are more common and sought after because they are more affordable than flawless diamond yet still have very minor inclusions, most of which can only be seen under magnification by a skilled grader. Likely the most common clarity grade is SI (slightly included). Diamond of this clarity are still considered “eye-clean” and provide an inexpensive alternative. The lowest clarity grade, I (imperfect), has more noticeable inclusions which may affect the brilliance of the diamond.
GIA defines their clarity grading scale as follows:
* Flawless (FL)
No inclusions or blemishes are visible to a skilled grader using 10x magnification
* Internally Flawless (IF)
No inclusions and only minor blemishes are visible to a skilled grader using 10x magnification
* Very, Very Slightly Included (VVS1 and VVS2)
Inclusions are difficult for a skilled grader to see under 10x magnification
* Very Slightly Included (VS1 and VS2)
Inclusions are clearly visible under 10x magnification but can be characterized as minor
* Slightly Included (SI1 and SI2)
Inclusions are noticeable to a skilled grader using 10x magnification
* Imperfect (I1, I2, and I3)
Inclusions are obvious under 10x magnification and may affect transparency and brilliance
The weight of a diamond is measured in carats, with one carat equaling 200 milligrams or 1/5 gram. You may also hear the term “points” used when speaking of diamond weight. One carat is divided up into 100 points, so a 1/4 carat diamond would be referred to as a ’25 point diamond.’
Although carat weight is also used to measure gemstones, it is slightly more complicated, since gemstone types may have different densities. Because of this, a round 6mm Alexandrite may have a carat weight of 1.30ct whereas a round 6mm Citrine may only be 0.70ct.
When written, carat is usually abbreviated as ‘ct.’ In a jewelry piece with several diamond, the abbreviation used is ‘ct TW’ meaning carat total weight (the sum of the carat weights for each diamond), although that’s usually shortened to ‘ctw.’ The value of such a jewelry piece may be less than the value of a similar item of the same carat weight with only 1 diamond. Diamond solitaires are much more rare, and therefore, a 1ct Diamond Solitaire ring will be worth much more than a similar 1ctw ring with many smaller diamond.